MLA International Bibliography - The most important database for research in literature, folklore, linguistics and more.
Academic Search Complete - A good general database for scholarly peer-reviewed articles. Use the "Choose Databases" link at the top of the page to cross-search Historical Abstracts, Humanities International Complete, or America: History and Life, depending on your topic.
Historical Abstracts - History journal articles covering the period 1450 to present. Excludes topics in U.S. and Canadian history.
JSTOR - Full-text scholarly journal articles from older issues.