Medical Textbooks in the Reserve Collection
Electronic Online Textbooks
Differential Diagnosis Generator
Consider limiting your search by language, dates once results are noted.
To find a few good articles consider limiting your search to the subset "Core Clinical Journals" found on Advanced Search page (link on the upper left of the page).
Another good place to start is the Clinical Queries page...look for link at the bottom of the homepage for PubMed or the bottom of the Advanced Search page.