Reference sources (encyclopedias, catalogs, dictionaries etc.) can be useful to get an overview of topics you may be interested in researching and to develop your research question. The more background information you have on a topic of interest, the more you will be able to think of promising research questions. These reference sources, in addition to academic journals and magazines, are a good place to start looking for film reviews.
"The Women Film Pioneers Project (WFPP) is a freely accessible, collaborative online database that showcases the hundreds of women who worked behind-the-scenes in the silent film industry as directors, producers, editors, and more. Always expanding, the database features career profiles on each pioneer, longer overview essays on national cinemas and occupations, still and moving images, and archival and bibliographic resource materials."