Databases for Journal Articles and Essays
Searching in the Everything mode will bring up articles, both academic and non-scholarly. If you wish, you can limit your search results to peer-reviewed articles, and refine them further by language, publication date, subject, etc.
MLA International Bibliography
An essential index to scholarly studies of literatures around the world and from all time periods. The MLA also covers work in related fields such as folklore and mythology, linguistics, theory, film, and popular culture.
Literature Online (LION)
In the Advanced Search, choose the search page for Criticism. There’s considerable overlap with the MLA International Bibliography, but it’s still worth searching both. LION is especially useful for finding work by UK-based scholars, as well as academic book reviews (which the MLA specifically excludes).