Free online peer reviewed journals

General directories

 * Directory of Open Access Journals
 * Free Medical Journals
 * Highwire Press freely available journals - many journals not completely free, but it tells you when the free access for articles starts for each journal
 * Education-line

Multitopic

 * arXiv - Electronic preprint archive for Physics, Mathematics, Computer Science and Quantitative Biology, orginial public domain science database started in 1991
 * Philica - Instant academic publishing with transparent peer-review for articles on any subject

Agriculture and fisheries

 * Agronomy Journal - all except 2006 issues freely available
 * Crop Science Journal - all except 2006 issues freely available
 * Soil Science of America Journal - all except 2006 issues freely available
 * Acta agriculturae Slovenica - all issues available. Seems two-thirds of content is in Slovenian, the other third in English.
 * Vadose Zone Journal - all except 2006 issues freely available
 * Agraarteadus - Journal of Agricultural Science - all issues available - all content in both Estonian and English.
 * Journal of Environmental Quality - all except 2006 issues freely available
 * Journal of Natural Resources and Life Sciences Education - all issues including and before 2004 freely available (see 'archived issues')
 * Agricultura Técnica - all issues available - all articles in Spanish, all abstracts also available in English. Some articles are in English as well as Spanish.
 * Agricultural Engineering International - all issues available
 * Agrociencia - all issues available - from 2000 onwards all articles are in both Spanish and English. Before 2000 I don't see any English articles, though I might be wrong.
 * Agronomy Research - all issues available - Estonian journal all in English.
 * Annals of Agricultural and Environmental Medicine - all issues seemingly available
 * Applied Ecology and Environmental Research - all issues available
 * Biotechnology, Agronomy, Society and Environment - all issues available, only some in English (mostly in French)

Computer science

 * INFOCOMP Journal of Computer Science
 * Journal of Object Technology
 * Journal of Computing

Earth science

 * Oil Shale - all issues since 1990 available

Education

 * Journal of University Teaching & Learning Practice (open access, but restricted copyright)

Mathematics

 * Bulletin of the American Mathematical Society

Medicine

 * WikiJournal of Medicine

Internet and technology

 * First Monday
 * Computers and composition digital press

Psychology

 * Psychology/Journals

Qualitative research

 * Forum:Qualitative Social Research (in English and German)