The standard index to economic literature, from the American Economic Association. Books, articles, working papers...
Business Source Complete
Index and full-text of thousands of trade and scholarly publications in business, economics, and related fields. Also includes various market research reports, company research reports, and country research reports.
Web of Science (Social Science Citation Index).
Key feature is citation index, which finds items which cite other items. You may create a 'web' of research on a topic, find out who and how many are citing you, etc. It may also be used to identify works by author, topic. etc.