ClinicalKey is a great resource to use for background information. For example, if you would like to learn more about a disease or condition, including the pathophysiology, typical disease progression, and different testing and/or treatment options.
ClinicalKey contains a wide variety of popular medical textbooks, such as Ferri's Clinical Advisor, Davidson's Principles and Practice of Medicine, Rosen's Emergency Medicine, and more.
It also contains MEDLINE articles, Clinical Overviews, Practice Guidelines and Drug Monographs.