BioMed Central
http://www.biomedcentral.com/home/
All original research articles published by BioMed Central are made freely and permanently accessible online immediately upon publication. BioMed Central views open access to research as essential in order to ensure the rapid and efficient communication of research findings.
Entrez PubMed
http://www.ncbi.nlm.nih.gov/entrez/
PubMed offers free, online access to the National Institute of Medicine’s MEDLINE databases. The site provides access to citations and abstracts from biomedical literature. If a publisher has a web site that offers full-text of its journals, PubMed provides links to that site as well as biological resources, consumer health information, research tools, and more. While there are some free full-text articles available, many publishers charge a fee for access to full-text.
HealthWeb
http://healthweb.org/
HealthWeb is a joint project of the Committee on Institutional
Cooperation (CIC) member health sciences libraries. Each of the CIC
member libraries has subject areas in which they have special expertise,
known as "areas of excellence." Working from these areas of excellence
has made it possible to provide coverage of evaluated,non-commercial,
health related Internet sites.
MedScape
http://www.medscape.com/
Users of this site must register. The user then selects a subject site. There is no "homepage" but users can select other subjects or search. Free MEDLINE is available as well as value added news and reviews and full text of selected journal articles and textbooks.
Public Library of Science
http://www.plos.org/
The Public Library of Science is a nonprofit organization that publishes freely available open access journals covering all aspects of life science and medicine. PLoS publishes peer-reviewed scientific and medical journals that include original research as well as timely feature articles.