Provides free (open) access to e-prints in Physics, Mathematics, Computer Science, Quantitative Biology, Quantitative Finance and Statistics.

BMC has an evolving portfolio of some 300 peer-reviewed journals, sharing discoveries from research communities in science, technology, engineering and medicine.

bioRxiv (pronounced "bio-archive") is a free online archive and distribution service for unpublished preprints in the life sciences.

ChEMBL is a manually curated database of bioactive molecules with drug-like properties. It brings together chemical, bioactivity and genomic data to aid the translation of genomic information into effective new drugs.

Nature Communications is an open access journal that publishes high-quality research from all areas of the natural sciences. Papers published by the journal represent important advances of significance to specialists within each field.

Bookshelf provides free online access to books and documents in life science and healthcare.

OSTI.GOV is the primary search tool for DOE science, technology, and engineering research and development results and the organizational hub for information about the DOE Office of Scientific and Technical Information. It consolidates OSTI’s home page and our now retired primary search tool SciTech Connect.

PhilSci-Archive includes pre-prints of scholarly works in all areas of philosophy of science, including general philosophy of science, philosophy of particular sciences (physics, biology, chemistry, psychology, etc.), feminist philosophy of science, socially relevant philosophy of science, history and philosophy of science and history of the philosophy of science.

PLOS ONE is a multidisciplinary open access journal that features reports of original research from all disciplines within science and medicine. By not excluding research on the basis of subject area, PLOS ONE facilitates the discovery of connections between research whether within or between disciplines.

Selected math and statistics journals from a variety of publishers hosted by Project Euclid.

PubMed Central® (PMC) is 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).

Open access journals and books from Science Direct.

Science.gov searches over 60 databases and over 2,200 scientific websites to provide users with access to more than 200 million pages of authoritative federal science information including research and development results.

Wiley Open Access publishes authoritative peer reviewed open access journals across many research disciplines.