DOAJ is an online directory that indexes and provides access to quality open access, peer-reviewed journals.

OMICS Group International is an amalgamation of Open Access publications and worldwide international science conferences and events. Established in the year 2007 with the sole aim of making the information on Sciences and technology ‘Open Access’, OMICS Group publishes 500 online open access scholarly journals in all aspects of Science, Engineering, Management and Technology journals.

PubMed Central (PMC) - 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). 

PMC International (PMCI) is a collaborative effort between NIH and NLM, the publishers whose journal content makes up the PMC archive, and organizations in other countries that share NIH's and NLM's interest in archiving life sciences literature. The long term goal of PMCI is to create a network of digital archives that can share all of their respective locally deposited content with others in the network.