arXiv
arXive (pronounced ‘archive’) is a repository of moderated (but not peer-reviewed) electronic preprints, consisting of scientific papers in the fields of mathematics, physics, astronomy, electrical engineering, computer science, quantitative biology, statistics, mathematical finance and economics.
BioMed Central
BioMed Central is a publisher of science, technology and medicine journals, incorporating the biomedicine, physical sciences, mathematics and engineering disciplines.
Clarivate Analytics
Clarivate Analytics owns and operates a collection of subscription-based services focused largely on analytics, including scientific and academic research.
CyberLeninka
CyberLeninka is a non-profit Russian open access scientific library, covering the natural sciences, social sciences, humanities, engineering and technology.
De Gruyter
De Gruyter is an independent academic publisher of peer-reviewed open access scholarly books and journals.
Elsevier
Elsevier is a Dutch information and analytics company and one of the world’s major providers of scientific, technical and medical information.
Hindawi
Hindawi is a commercial publisher of peer-reviewed open access scientific, technical and medical literature.
PLOS
PLOS (Public Library of Science) is a scientific (life sciences) and medical open access publishing venture.
ResearchGate
ResearchGate is a professional network for scientists and researchers. The portal is also used to share research outputs.
SSRN
SSRN (formerly Social Science Research Network) is an open-access online preprint community. The portal provides access to scientific papers primarily in social sciences, including economics, law, corporate governance and humanities. Most of the papers are available to download for free.