THE database for medical and health sciences research. More than 25 million references to journal articles in life sciences with a concentration on biomedicine. See also PubMed (freely available). To find primary/research articles, under Search Options, try limiting to Publication Types "clinical trial" and/or "randomized controlled trial." To limit to review articles, leave Publication Types set to "All" and click the Review Articles box.
Not always the best place to start your search (search options are limited; consider starting in a library database), but a great resource for finding full text and seeing "cited by" counts. Freely available.
Includes all of MEDLINE plus life science journals and online books. Freely available, so you'll be able to use it even after graduation. MEDLINE is better integrated with the rest of the library's resources.