PubMed Central (PMC) is the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature. The PMC journal list comprises journals that deposit material in PMC on a routine basis and generally make all their published articles available.

BioMed Central - the Open Access Publisher. Publisher of 194 peer-reviewed open access journals.
Subject Areas : The research articles in all journals published by BioMed Central are 'Open Access'. They are immediately and permanently available online without charge. A number of journals require an institutional or a personal subscription to view other content, such as reviews or paper reports. Free trial subscriptions to these journals are available.

Directory of Open Access Journals - List from Lund University, Sweden. This service covers free, full text, quality controlled scientific and scholarly journals.

Free Online Full-text Journals - from Highwire Press publishers: HighWire Press is the largest archive of free full-text science on Earth! As of 10/15/08, we are assisting in the online publication of 1,965,289 free full-text articles and 4,877,693 total articles. There are 18 sites with free trial periods, and 44 completely free sites. 256 sites have free back issues, and 1092 sites have pay per view!

Medknow Publications - Open access, peer-reviewed, indexed, scholarly journals. Contains 73 journals many located in Africa, Asia, and India.

Public Library of Science - PLoS is a nonprofit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource.Non-profit organization of scientists and physicians