A two-credit course in the techniques and tools for effective searching the literature of chemistry, biochemistry, chemical engineering and related fields.
Lecture 11" Introduction to Chemical Abstracts Online
Chemical Abstracts Online
Just as Chemical Abstracts is the single most important printed tool for chemical information, so its online counterpart is the most important electronic source.
Electronic CA is made available through several vendors, including DIALOG, Orbit/Questel, and STN International, and in several formats, including STN Online, STNEasy (web menu interface), STNWeb (web command interface), SciFinder, and SciFindern. We will be primarily using SciFinder.
STN International
STN International is a cooperative service of three database providers:
Forst released in 2017 as a total revision of the previous SciFinder web interface. It now gets regular featue updates on a monthly basis.
Pricing is by annual institutional subscription.Pricing is determined by a complex formula based on the number of total users, the size and location of the institution. Unlimited simultaneous user subscriptions are now available, and virtually all academic institutions, including the University of California, now have unlimited users.
SciFinder-n allows searching for:
References - Underlying databases are CAPlus and MEDLINE.
Substances - Underlying database is CA REGISTRY.
Reactions - None: Organic reactions only. Underlying database is CASREACT
Suppliers - Underlying database is CHEMCATS
Biosequences - Database of 500M polypeptide and polynucleotide sequences from the patent literture. In the near future, you will also be able to search the 60M+ sequences from the journal literature in CAS REGISTRY.
It incorporates the PatentPak and MethodsNow organic synthesis products incorporated for no aditional charge.The Chemisches Zentralblatt database, Methods Now analytical and Formulus remain as separate, extra cost products.
It allows simultaneous searching of text and structures, and obtains document, substance and reaction results (reminiscent of the new Reaxys interface.
It has a custom relevance sorting algorithm to bring the most chemically relevant answers to the top of your list.
It has sophisticated filtering options for powerful refinement of answer sets.
It has a "citation map" simultaneous display of cited and citing references for a selected paper.
IIt now has a retrosynthetic planning tool which uses artificial intelligence to identify synthesis routes for both previously synthesized bubtances, and for substances which have not yet been synthetically prepared.
It incorporates the Chemscape and Bioscape visualization stools to assist in analysis of answer sets - particularly patent answer sets.
In SciFinder-n at present, you can search the following (see also CAS Content (https://www.cas.org/about/cas-content )
The Chemical Abstracts document database (CAPLUS). Documents from 1907 to the present (plus selected records pre-1906) have bibliographic information, abstracts, and full subject and substance indexing (by CAS Registry Number.) Total number of records: over 56 million as of Feb. 2022. Updated daily.
The Chemical Abstracts substance file (REGISTRY). Substances indexed by Chemical Abstracts since 1957, plus substances from other sources (regulatory agencies, chemical catalogs, etc.) Includes Registry Numbers, chemical names, molecular formulas. Searchable structure diagrams are available for most simple compounds. Many proteins and nucleic acids have sequence information (displayable but not directly searchable in SF). Many compound records have predicted and/or experimental chemical data for selected properties. In SF, this information cannot be searched directly, but can be used to refine searches. Over 234 million records as of Feb. 2022 (over 193 million simple substances; over 69 million biosequences (polypeptides and polynucleotides)). (Note: CAS is in the process of adding a huge number of additinal biosequences.Updated daily.
The Chemical Abstracts reaction file (CASREACT). Organic reactions from journal literature from 1840 to present, and patents from 1982 to present, as well as reaction sources like Organic Reactions, Organic Syntheses and Encyclopedia of Reagents for Organic Synthesis. Structure searchable for reactants and products, with reaction sites and atoms specifiable. Over 100,000 documents indexed, with over 141 million reactions as of Feb. 2022. Updated daily. Note that raction references in SciFinder-n include, where available, detailed reaction descriptions from MethodsNow.
The Chemical Abstracts Markush patents file (MARPAT). Markush structure records for patents found in CAplus with the patent publication year of 1988 to the present, including coverage of Russian patents published after January 10, 2000. Over 1.3 million Markush structures, from over 650,000 patent records. Note that while Markush structures are searchable in SciFinder, the records displayed are the CAPlus records for the patents, without some of the special display features of the MARPAT file. Updated daily.
MEDLINE (This is the database available free to the public as PubMed). The National Library of Medicine's database may be searched simultaneously with the CAPLUS database in SciFinder. More than 26 million records are available from 1946 to present as of Feb. 2019. It currently indexes almost 4,800 biomedical journals (with considerable overlap with CAPLUS.) The database is updated five times/week, with a complete annual reload to update subject headings. Note that in SciFinder-n, when a document is indexed in both CAPLUS and MEDLINE, the records are merged, and you can see both the CA Concept Headings and the MeSH hsubject headings associated with the article.
ChemZent The German chemical index, Chemisches Zentralbatt, covering the years 1830-1969, has been digitized and translated into English and male available in SciFinder-n, and is simultaneously searchable along wiht the CAPLUS and MEDLINE references, providing additional intormation on 20th century chemistry, and references from the early history of chemistry that are availalable nowhere else , especially valuable for patent prior art searching. CAS editors have added the linkages to the REGISTRY substance records.
The Chemical Abstracts chemical catalogs file (CHEMCATS). Information (including pricing) on over 98 million products covering over 32 million unique Registry Number from over 1740 suppliers' catalogs and chemical libraries as of Dec. 2015. Updated weekly.
Biosequences - In addition to the protein and nucleic acid sequences indexed in the Registry file, CAS has acquired a fle of hudreds of millions of sequences from the patent literature, as well as the NCBI (National Centr for Biotechnology Information) protein and nucleic acid databases, for a total of OVER ONE BILLION sequences that are searchable in SciFinder-n.
Additionally:
The Chemical Abstracts chemical regulatory database (CHEMLIST). Lists regulatory information from over 150 national and international agencies on over 417,000 substances as of SFeb. 2022. In SciFinder,-n, regulatory information is linked to substance records but may not be directly searched. Updated weekly.
Formulus formulations indexing is added to document records where it is available. The full information from Formulus is a separate database on the SciFinder Discovery platform, and its full data is not provided but some of the information on formulations indexed in the document is available, and you can refine answer sets to those answers containing Formulus data. S Formulation Purpose filter option will appear in References answwer sets where one or more Forumulus identified compounds appear.
CAS Analytical Methodsl data is also linked to document records where available. Again, CA Analytical Metods is a separate prdocuct,on the SciFinder Discoery Platform, but the full methods details are not provided in the SciFinder records themselves, but the additional indexing can be a valuable hint as to whether the full article contains a detailed analytical method or not.
CAS Life Sciences - CA is currently developing a new product/solution which will incorporate vast quatities of SAR (structure-activity relationship) and ADMET (absorption, distribution, metabolism, excretion, and toxicity) data, along with target data, for bioactive compouns. At presnet, this data is being previewed though SciFinder-n, but it is expected that at some point in the near future, it will be spun off into a separate, added-cost, product.
Logging in to SciFindern
Note that this database requires registration (see above.) If you are logging in from off-campus, either use the campus VPN or the Library proxy server. If you use the links in the Library databases lists, our systems will automatically detect whether you are on-campus, already connected to the proxy or VPN, or off-campus and unconnected. If the latter, you will be automatically routed to a proxy server login screen. Once logged in, you will continue on to the SciFinder login page.
Enter your username or the e-mail address you used to register. A "Next" button will appear. Click it. On the next screen, enter your password, then click "Log in". Do NOT select :Keep me logged in" if you are using a plublic workstation.The system will remember your username/e-mail for future use unless someone else logs in on that workstation.
SciFindern Opening Screen
Note that the default opening screen is set for substance searching. If you have previously searched in this account, your recent search history will display below the search window.\
Breakdown of the Opening Screen
In the upper left is the CAS SciFinder-n logo. T
On the left are three vertically-arranged dots. Clicking on them opens a drop-down menu:
This enables the user to switch freely among CAS products. Note that you or your institution must subscribe to the product in question to access it, and at the moment, UCSB subscribes to SciFinder-n., CAS Analytical Methods and CAS Formulus. Switching from one to another requires logging in again, but the same CAS ID and password works for all three.
In the upper right are three options:
Clicking on Alerts takes you to a list of the search alrts you have created, if any, where you can view results, modify and update searches, etc.
Clicking on Saved takes you to the list of your saved searches, where you can view previous results or re-run the searches, turn them into alers, etc.
Clicking on your nameopens a drop-down menu:
What's New? takes you to a list of the most recent updates to the SciFinder-n interface.
Help opens a new tab, with help related to the screen you had been looking at, as well as a table of contents of Help topics, and a search window for the help topics.
My CAS Profile allow you to manipulate details of your SciFinder account
Log out lets you log out of your current session. (Note: Always be sure to log out when using public workstations!)
To the left of the screen is the menu for selecting whcih time of search you wish to do. By default, the highlighted choice whill be whichever type of search you did last.
Biosequences - Search for biosequences (proteins, polynucleotides) using various sequence searching options. See Lecture 13 for more details.
Retrosynthesis - Takes you to the SciFinder-n retrosynthesis tools which uses AI and the CAS sybstance database to allow you to create retrosyntheitc paths to both known and predicted substances. See Lecture 15 for details.
To the right of the Search Selection menu is the Search Window, which will vary by the type of search selected.. For searches involving substances or reactions, the window will include both a search term window, and a Draw icon to open the structure drawing tool (discussed in detail in Lecture 14). All search windows will have the magnifying class icon. Click on it to begin the search.
Below the search window is a drop-down menu for searching specific fields appropriate to the type of search you are conducting.. The "Add Advanced Search field" link lets you add additional fielded searches to combine with hou basic search.
Advanced Reference Searching in SciFindern
TSciFinder-n combines all the non-topic search options for References into Advanced Referece Search. When you select References from the search options on the lef-hand side of the screen, look for the Advanced Reference Search link underneath the main seaerch window.
FClick on the link and then you can select the type of search you wish to do from the drop-down menu, as well as the Boolean operator for combining it with other search options - the default is AND. The options are: Authors, Publication Name, Organization, Title, Abstract/Keywords, Concept,, Substances , Publication Year, Document Identfier., Patent Identifier or Publisher. Note the arrows next to Authors and Substances. The former lets you select Author Name or ORCID. The latter lets you select CAS Registry Number or Chemical Name.
Click on the preferred name (in this case, "Ford, Peter C") and then click the Search icon at the bottom of the page.SciFinder-n will automatically find variations on the name (in this case, "Ford, P C" and "Ford, Peter Campbell"). Note that this process is not perfect; you may want to try variations on the name, and use the "Add another author" option to OR the alternatives together.
For author searching, enter the author's last name first. As you begin entering the name, a drop-down menu of selected author names will appear. SciFinder-n has a degree of built-in intelligence that allows it to search for alternate forms of the author name which you select. Note that this can generate false hits in some cases.
Below are the results of the example author search.
References Answer Set
Below is the first part of a typical references answer set (derived from the search above.)
Breakdown of Reference Answer Set Display
Let us now survey this answer set display and identify its key elements.
At top: Note the basic search window. You can edit the existing search or enter a new search for references, substances or reactions directly from the answer set display.
To the right of the search icon, there is the Bell icon = View Saved Results, the Clock icon = View Search History, and the User icon =My Account
Immediately below the line on the left: Return to Home link
Below that, on the left: Filter Behavior options. You can select either Filter by or Exclude , then select one of the filter options and Apply it. your selection. Note that only options which are relevant to the search you have done appear in the column. Here we have:
Document Type
Language
Publication Year
Author
Organization
Publication Name (e.g. Journal Title)
Concept (e.g. CA Subject headig or MeSH Heading)
CA Section (where available, nams of the CA Sections applied to each document)
Bioactivity Data (Presence of Structure Activity Relationship (SAR) or Absorption, Distribution, Metabolism, Excretion, Toxicity (ADMET) data in the record.)
Database (CAPlus, MEDLINE or ChemZent)
Search Within Results
Not shown above - Filter Content Report - download tables of the filter content values for this answer set.
When you click on the drop-down menu for one of the Filter fields, you see the five most common results. If you then click on View All and there are 10 or fewer results, the list will simply expand. If there are more than 10 results, a pop-up window will appear displaying the full set. (Further explanation below.)
Below the filter list is the option to download a Filter Content Report, which allows you to download an Excel spreadsheet report of selected filter data from this answer set.
In the center: A large print description of what type of answer set you are viewing (in this case, References) and the total number of items in the set.
On the right: A drop-down menu of Sort options
Relevance This is the default sort. SciFinder-n uses a propriety algorithm to sort for relevance.
Times Cited
Accession Number Ascending
Accession NUmber Descending
Publication Date newest
Publication Date oldest
Next to that, a drop-down menu of Display options
No Abstract
Partial Abstract (this is the default option)
Full Abstract
Just above the list of answers:
If you have selected one or more answers (see below), a Selected tag will appear, with the number of selected answer and a box to deselect all.
Next, a drop-down menu for retrieving all the Substances indexed in selected answers or all answers
Similarly, a drop-down menu to retrieve all (organic) Reactions indexed in selected answers or all answers.
The Citing drop-down retrieves all documents which cite one or more of the selected or all answers in your stating set.
Knowledge Graph is a beta-test of a graphical visualization of the answer set, displaying (as you select) the authors, substances, concepts and , organizations extracted from the answer set. You may filter the answers displayed using most of the Filter options listed above.
One the right, there is a Combine icon. You may use Boolean operators to combine the current answer se with any of your saved answer sets.
Download icon. Clicking it opens a pop-up whidonw in which you can select the fields to download, assign a file name and choose a file format.
Note the options to download as PDF for easy printing; RTF for annotation and printing; Excel for spreadsheet manipulation and RIS for exporting to EndNote or other bibliographic reference software, among others.
Next is the envelope icon for E-mailing results. Note that the recipient must have their own SciFinder-n account to open the answer set. The recipient will then be able to manipulate the answer set just as if they had done the search temselves. If you want to send results to someone without an account, download the answer set and send the results as an attachment.
The bell Save and Alerts icon opens the menu of Save options.
From this menu, you can save selected answers or the answer set, as well as the search itself (including filters and other options) to your SciFinder-n account and access them whenever you log on. You may also Tag the saved results with one or more keywrotds, and, if you wish, assign a highlighting color to each keyword tag. You will give the search a name, and you may elect to create a search alert. This re-runs your search As available )that is, whenever new results are added to the database), Weekly or Monthly If new hits to your search are retrieved, you will receive an e-mail notification, and you can view the new hits in SciFinder-n. This is an extremely useful way to track new developments in field of interest, or new citations of documents you are following.
Brief Records for References
Above is a brief record for a journal article, taken from the answer set. Note the following features:
Above the answer is the record number for the answer in this answer set, and a check box. Click on the check box to Select this answer for saving, downloading, e-mailing, retriving substances, reactions, citing references, and so forth.
Next is the article title, as it appears in the article. Clicking on the article title takes you to the full record for the document (see below for a full record display.) Note: In this case, and most situations in SciFinder-n, if you right-click on an item, it opens in a new tab/wndow. This can be very handy for moving back and forth between elements of your search.
Below that are the author(s)name(s) as they appear in the article. In this case, Peter Ford's name is highlighted, since that is the search term that caused this item to be retrieved.
Below that are the journal name, year of publication, volume, issue, pages, This information, along with the authors and article title are what you would need to properly cite the article. Also on this line are the language of the article and source databases. Note that this article was indexed in both CAplus and AMEDLINE.
Below that is the brief abstract of the article (if that is the display option you selected), including an abstract image, if available.
Below that are tabs for connecting to Full Text, Substances (from the article), Reactions (from the article) and Citing (that is, references which cite the article) and Citation Map. Note that these tabs only appear if there is relevant material to link to - there is no Cited by tab for this article, as no article indexed by SciFinder-n has cited it. For journal articles, since you are logging in from a UCSB IP address (including the VPN and proxy server), you will usually see Get it at UC as an option for connecting to full text. Other types of rererence may have different full text sources.
Full Record - Journal Article
At top, just below the line: Return to Results takes you back to the full answer set.
Reference Detail - just to the right is the record number out of total number of records
Just below that are buttons to retrieve Substances and Reactions indexed in the document Citing records also appears if available.
The bell icon opens a pop-up to create a citation alert search; whenever an article citing this one is indexed, you'll get an e-mail alert.
Citation Map - creates (in a new window) a graphic display of articles cited by, and citing, the source document (see below for an example)
At right: Download, E-mail, Save and arrows linking to the previous and next document in the set.
In left-hand column:
Journal information - Journal name, Volume, Issue, Page numbers, Publication year, and (if available) DOI
Database information = Record ID numbers for CAplus and/or PubMed
Company/Organization - Name and address of the company/organization to which the corresponding author belonged at the time of publication.
Publisher - Publisher of the journal at the time of publication.
language - Language of the article.
Main body - Starts with the same information as in the brief record, followed by the rest of the abstract and any additional abstract graphics.
Keywords - These may be authr-assigned keywords, or keywords assigned by the indexer. All are searchable.
Full text link - Same as in brief record
Drop-down links for
Concepts - CA Conept aheadings and/or MeSH Subject headings assigned to the article, with associated subheadings See below for an example.
Substances - List of substances indexed in the document, including rsCAS Registry Number, 2D structures (when available), Molecular formulas (when available) Substance Roles in the document and Notes as to what information about the substance is contained in the document. Note: If you click on the cAS Registry Number for a substance, it will open the Substance Detail record for the substance. We will discuss Substance records extensivley in Lecture 13.
Structure Activity Relationships (if available and, until CAS Life Sciences becomes a separate product)
ADMET Data (if available and, until CAS Life Sciences becomes a separate product)
Cited regerences - Gives a list of the references cited in the article, in the order they appear in the document, with first author, abbreviated journal title, DOI if available, publcation year, volume, issue and first page. Note: If the cited article is indexed in SciFinder-n, the citation will be linked to the SciFinder-n record for the cited reference.Not all cited references have been so indexed.
Concepts Detail from a Journal Article Record
SciFinder-n Citation Map
Above is the citation map for one of Prof. Ford's most highly cited articles.
On the left: Tabs for
Filter by: You can limit the records displayed by Document Type, Author, Concept or Language
Cited by: Lists the articles citeb by the parent article in descending order of the total number of times those articles havve been cited in SciFinder-n documents. The darker the background, the more the document has been cited. You may click on the box to open a pop-up box with a brief document record. Clicking on the title in the box takes you t othe doument record, or you can click on Map this recorrd to see a citation map for that document.
Citing: Lists the articles which currently cite the parent document, in descending order by the number of times thy are cited. Documents boxes work the same way as in Cited by above.
In the citation map itself;
Hovering your cursor over one of the dots shows you the document record for that cited or citing document.Note that if you are displaying the list that the document appears in, it will scroll to that point in the list.
You can drag the map around, and zoom in and out with your cursor and mouse wheel.
At the bottom of each row of dots, there is (if necessary) a Show more link.
Full Record of a Patent
Here's the upper portion of the full record for a patent document:
Left-hand side - Patent information includes Patent number, Publication date, Application number, Application date, and Kind code. The paent number is key for locating the patent in other sources. The application date is key for establishing priority date if one is trying to determin whether there is prior art involving the invention.
Assignee - The name(s) of the person(s) or entities to whom the patent rights have been assigned. Note that patens by UC inventors are assigned to the Regents of the University of California.
Source: The country or intenational organization that issued the patent.
Database information The document ID number for the database, in this case, CAplus.
Main body of the record - The top of the record is very similar to that for a journal article, with title, inventors, brief abstract and keywords. Below that is the full text link, which for a patent usually includes Espacenet, the European Patent Office's website. For recent patents, like this one, there will usually also be a PatentPak viewer link, which takes you to a specially marked PDF copy of the patent, set up for easy location of substances described in the patent.
Patent family - Here is the information on all the different national and international patents that have been issued for this invention. The are listed in tabular form, with the following informatino for each patent: Patent, Language, Kind Code, PatnetPak Options Publication Date, Application Number and Application Date.
The priority patent is the first one listed.
Below the absract and family data, you'll find Concepts, Substances and Cited Documents, as in a journal article record, as well as, where availble, IPC Data - the International Patent Classification Codes for patents in this family. Note that this data is, at present, not searchable, only displayable.
Using Filters in SciFinder-n
This section deals with the filters available after an author search. Other filters for references, substances and reactions will be covered in later lectures.
Before you select a filter, first click either the Filter by or Exclude tab, depending on which you wish to do.
Generally speaking, if you click the check box next to a filter item, SciFinder-n will then automatically narrow your answer set to the answers meeting the filter criterion. Unchecking the box reverses the process. You may have multiple filters checked at once.
Document Type - Only those document types present in the answer set will be displayed. Only the five most common types will be initally displayed; if there are more, you'll see a View More link. Clicking on it will expand the list.Note: Review refers to scholarly review articles., not book reviews. All review articles are also considered Journal articles.
Language - Fairly obvious. Note that non-English documents have titles and abstracts translated into English in the doument record. Note also: For patents, the language is that of the priority patent. For a thorough search, do not exclude patents by language, since there may be other members of the patent family in a language that you can read.
Publication Year - The bar chart displays the range of publication years in your answer set on the x-axis. The y-axis corresponds to the number of references in that year.Hovering your cursor over a given bar will display the year and number of rererences. You may enter a staring and finishing range of years in the boxes below the chart. Click Apply to execute the filter. Selected years will be highlighted on the par char. If you wish to see a larger version of th bar chart, click the View Larger buttonReset cancels the Publication Year filter.
Author, Organization, Publication Name and Concept will all frequently have too many entrries to display in the left-hand column. To view them, first click the heading to crop-down the top five items then click View All to get a pop-up window with the full list. An example of an Author list is shown below.
T
Note the tabs at the top of the chart. The default display is by Top Count, that is, from most frequently appearing to least frequently appearing. You may also select Alphanumeric which sorts the results from A to Z. The third tab is Search which allows you to search within the list. Note, too, the scroll bar on the right. For a long list, you may beed to scroll down the page to see everything...or use Search to find what you're looking for.Search does let you truncate terms with an asterisk, for example, Photosynth* to find multiple forms of the word.
Note that if you select more than one item from the list, the items are treated as alternatives, that is, connected by OR. There is, at present, no way to AND together three of more of the same kind of search field except by creating separate searches and combining them on the Saved Searches page.
Note that for Authors, each form of an author's name is listed separately. It's best to display the list alphanumerically to better see all te forms together. Note that compound names and transliterated names may appear with different spellings.
Publication Name - Generally speaking, this refers to journal titles, but may include other types of publication ames as well, such as the name of the issuing country for patents.
Concept - This includes both CA Concept Headings and MeSH Subject Jeadings.. It is frequently a good idea to search for alternate forms of concepts you are interested in. Use truncation to see the most possibilities.
Database - This lets you filter according to the source database, CAPlus, MEDLINE or ChemZent. It is rarely useful
Search within Results - This lets you search for a keyword within your answer set. To use it, click on Search within Results. A text box will appear below the heading. Enter your tem there (asterisks, Boolean operators and parentheses may be used) and click the Apply button which appears.. To canclel the search and return to the original answer set, click the X next to your search term. Name Search
Publication Name Search
Going back to eh Advanced Reference Search options, here's the screen which appears when you select Journal Name search.
Note that in addition to the journal name itself, you can optionally add voume number, issue number and/or starting page. This option is highly useful for locating specific known articles, or verifying questionable journal references. Note in the example below, a drop-down menu with suggested search terms appears when you begin entering your search terms, and that there is a degree of buitl-in intelligence that can recognize journal abbreviations.
Organization Name Search
As with author name searches, as you start to enter an organization name, there will be a drop-down menu of suggestions. Note, however, tha tthe system does not display all possible organization names, or does it aautomatically catch all name variants. For example, University of California , Santa Barbara does not automatically catch uc santa barbara or ucsb.
If you wish to be complete, you may wish to create a separate search field for each alternative nme and OR them together a in the example below.
Title, Abstract/Keywords, Concept
Each of these is a more restrictive variant on general topic searching (see Lecture 12 for an in-depth discussion. Title limits the search to words apearing in the title of the document. Abstact/Keyword to terms appearing in those sections
Concept searches the subject headings assigned to the doment by the expert indexers - CA Subject Headings for CAS indexers and MesH headings for MEDLINE indexing. As noted above, in SciFinder-n, the records for documents which appear in both databases are combined and the concept headings from both are searchable in the single record. When you start entering a cocope search, a drop-down menu of available search terms appears, as in the example below.
Substances
Substance seaerching within the Reference search option is not as powerful as the main Substance search tool. However, it can be useful if you are combining a substance term witth, say, an author name or names, and/or a concept term. Note that in addition to the CAS Registry Number and Chemical Name options, you can also draw structures by clicking on the Draw tool next to the Search button. Substance searching will be treated in much greater detail in Lecture 13, and searching by structure drawing in Lecture 14.
Publication Year
Publication Year searching lets you specify a beginning year, an ending year, or both. It is rarely used by itself, but can be useful to limit other searches.
Document Identifier, Patent Identifier
These two options are usef for finding the records for known documents. Document Identifiers include CAS Accession Numbers (CAN) and Digital Object Identifiers (DOI). Patent Identifiers include patent numbers and patent application numbers.Identifiers must be entered exactly, and ther is no drop-down menu of suggestions for identifiers.