Content Provider
DataCite Metadata Store (German National Library of Science and Technology)
8,088
Arctic Data Center (via DataONE)
100
Defense Technical Information Center: DTIC Technical Reports database
47
PANGAEA - Data Publisher for Earth & Environmental Science
39
NOAA NCEI Environmental Data Archive (via DataONE)
24
University of Alaska: ScholarWorks@UA
24
Unknown
24
Ohio State University (OSU): Knowledge Bank
19
University of Calgary Journal Hosting
16
North Dakota State University (NDSU): Digital Horizons
14
Directory of Open Access Journals: DOAJ Articles
13
University of Washington, Seattle: Digital Collections
12
Zenodo
8
Copernicus Publications: E-Journals
7
Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center)
6
Cambridge University Press
6
NASA Technical Reports Server (NTRS)
6
Research Data Australia (Australian National Data Service - ANDS)
6
University of California: eScholarship
6
Washington State University: WSU Libraries Digital Collections
6
WikiBooks - Open-content textbooks
6
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe)
5
Niedersächsisches Online-Archiv NOA
5
PubMed Central (PMC)
5
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy)
5
Utah State University: DigitalCommons@USU
5
Digital.CSIC (Spanish National Research Council)
4
ScholarsArchive@OSU (Oregon State University)
4
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server)
4
Australian National University: ANU Digital Collections
3
Cambridge University Press (via Crossref)
3
Hathi Trust Digital Library
3
HighWire Press (Stanford University)
3
IEDA: US Antarctic Program Data Center (via DataONE)
3
MDPI Open Access Publishing
3
National Institute of Polar Research Repository, Japan
3
The Portal to Texas History (University of North Texas)
3
UTSA Digital Collections (The University of Texas at San Antonio)
3
University of St Andrews: Research Portal
3
Utrecht University Repository
3
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer)
2
Arctic Institute of North America (via Crossref)
2
Arctic and Antarctic Research (E-Journal)
2
Biological and Chemical Oceanography Data Management Office (BCO-DMO) (via DataONE)
2
CONICET Digital (Consejo Nacional de Investigaciones Científicas y Técnicas)
2
David Rumsey Historical Map Collection (Cartography Associates)
2
Dryad Digital Repository (Duke University)
2
Flanders Marine Institute (VLIZ): Open Marine Archive (OMA)
2
IEDA: EarthChem Library (via DataONE)
2
LAEI VL (Lithuanian Institute of Agrarian Economics Virtual Library)
2
more ...