The OSF Preprints search combines records from various preprint repositories, including arXiv, bioRxiv, Cogprints, PeerJ, PsyArXiv, RePEc and SocArXiv.

The SAO/NASA Astrophysics Data System (ADS) is a digital library portal for researchers in astronomy and physics, operated by the Smithsonian Astrophysical Observatory (SAO) under a NASA grant. The ADS maintains three bibliographic databases containing more than 13 million records covering publications in Astronomy and Astrophysics, Physics, and the arXiv e-prints. Abstracts and full-text of major astronomy and physics publications are indexed and searchable through the new ADS modern search form as well as a classic search form.

ScienceOpen is a networking platform for scholars to enhance their research in the open, make an impact, and receive credit for it. The site provides advanced search and discovery functions, combined with post-publication peer review, recommendation, social sharing, and collection-building features. The Max Planck Society covers article-processing charges for ScienceOpen Research and ScienceOpen Poster centrally. Further details are available on the MPDL website.