PubMed Central (PMC) is a free digital archive of full-text scholarly articles in the biomedical and life sciences, maintained by the U.S. National Institutes of Health’s National Library of Medicine.
The Directory of Open Access Journals (DOAJ) is a communit y-curated online directory that indexes and provides access to high-qualit y, peer-reviewed open access journals from around the world.
The Public Library of Science (PLOS) is a nonprofit open access publisher that aims to accelerate progress in science and medicine by publishing a collection of peer-reviewed journals.
The Multidisciplinary Digital Publishing Institute (MDPI) is a Swiss-based, open-access academic publisher that publishes a large portfolio of peer-reviewed scientific journals.