BioMed Central: BioMed Central (Open Access Publisher) publishes 236 peer-reviewed open access journals.
Directory of Open Access Journals: Free, full text, quality controlled scientific and scholarly journals, covering all subjects and many languages.
PubMed Central: PMC is a free full-text archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health's National Library of Medicine (NIH/NLM).
Free Medical Journals: List of free medical journals.
Free online Full-Text Journals: List limited to journals published online with the assistance of HighWire Press.
eMedicine: This resource is from Medscape. Medscape is the leading online global destination for physicians and healthcare professionals worldwide, offering the latest medical news and expert perspectives; essential point-of-care drug and disease information; and relevant professional education and CME.
Medscape membership is free and gives you unlimited access to the entire network of sites and services.
Bookshelf from NCBI: Bookshelf provides free access to books and documents in life science and healthcare. A vital node in the data-rich resource network at NCBI, Bookshelf enables users to easily browse, retrieve, and read content, and spurs discovery of related information.
The Merck Manual: The Merck Manuals are medical references published by the American pharmaceutical company Merck & Co., that cover a wide range of medical topics, including disorders, tests, diagnoses, and drugs. The manuals have been published since 1899. They are available in several languages.
Disease Management: The Disease Management Project is an online medical reference, designed to provide nationally established treatment guidelines for the most commonly seen diseases and conditions.