Content Provider
DataCite Metadata Store (German National Library of Science and Technology)
1,278
NOAA NCEI Environmental Data Archive (via DataONE)
95
Unknown
47
LeibnizOpen (The Leibniz Association)
39
Missouri State University: Digital Collections
33
Directory of Open Access Journals: DOAJ Articles
18
PubMed Central (PMC)
17
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe)
15
North Dakota State University (NDSU): Digital Horizons
14
Washington State University: WSU Libraries Digital Collections
13
WikiBooks - Open-content textbooks
12
The University of Utah: J. Willard Marriott Digital Library
11
Université de Nantes: HAL-UNIV-NANTES
11
HighWire Press (Stanford University)
10
University of St Andrews: Research Portal
10
Cambridge University Press
9
RePEc (Research Papers in Economics)
9
Defense Technical Information Center: DTIC Technical Reports database
8
Hunter Library Digital Collections (Western Carolina University)
7
University of Southampton: e-Prints Soton
7
Institut national des sciences de l'Univers: HAL-INSU
6
Magnolia press
6
Opin vísindi (Iceland)
6
PANGAEA - Data Publisher for Earth & Environmental Science
6
Skemman (Iceland)
6
Wiley Online Library
6
Copernicus Publications: E-Journals
5
Dryad Digital Repository (Duke University)
5
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam)
5
Ghent University Academic Bibliography
5
Peking University Institutional Repository (PKU IR)
5
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy)
5
The University of Queensland: UQ eSpace
5
University of North Texas: UNT Digital Library
5
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server)
5
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer)
4
Digital.CSIC (Spanish National Research Council)
4
Flanders Marine Institute (VLIZ): Open Marine Archive (OMA)
4
Natural Environment Research Council: NERC Open Research Archive
4
Pensoft Publishers
4
Rice University: Digital Scholarship Archive
4
University of Bristol: Bristol Research
4
University of Cambridge, Department of Earth Sciences: ESC Publications
4
University of Cumbria: Insight
4
University of Malta: OAR@UM
4
University of New Hampshire: Scholars Repository
4
University of Washington, Seattle: Digital Collections
4
University of the Pacific, McGeorge School of Law: Scholarly Commons
4
University of the Pacific: Scholarly Commons
4
Australian National University: ANU Digital Collections
3
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