DOAJ contains over 15, 000 peer-reviewed open access journals covering all areas of science, technology, medicine, social sciences, arts and humanities.

NLM is the world’s largest biomedical library.

SSRN provides 950,733 research papers from 503,172 researchers in more than 60 disciplines.

SpringerOpen, includes Springer’s portfolio of 200+ peer-reviewed fully open access journals across all areas of science.

Wiley Open Access journals publishes a number of online journals across biological, chemical and health sciences.