Content Provider
Open Parks Network
9,254
DataCite Metadata Store (German National Library of Science and Technology)
5,764
Unknown
2,494
University of Alaska: ScholarWorks@UA
2,265
Washington State University: WSU Libraries Digital Collections
1,905
Directory of Open Access Journals: DOAJ Articles
1,814
PANGAEA - Data Publisher for Earth & Environmental Science
1,620
Defense Technical Information Center: DTIC Technical Reports database
1,118
University of Calgary Journal Hosting
970
Wiley Online Library
926
Wiley Online Library (via Crossref)
885
University of the Pacific, McGeorge School of Law: Scholarly Commons
837
University of the Pacific: Scholarly Commons
836
Cambridge University Press
764
PubMed Central (PMC)
714
Hathi Trust Digital Library
691
University of North Texas: UNT Digital Library
673
Canadian Science Publishing (via Crossref)
536
ScienceDirect (Elsevier - via Crossref)
505
Biodiversity Heritage Library (BHL)
486
The Library of Congress: American Memory
483
University of Florida: Digital Library Center
422
Copernicus Publications: E-Journals
406
Springer Nature (via Crossref)
320
Informa (via Crossref)
310
The Seattle Public Library Special Collections Online
303
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe)
300
Niedersächsisches Online-Archiv NOA
289
APS Digital Library (American Philosophical Society)
280
Canadian Science Publishing
261
HighWire Press (Stanford University)
261
MDPI Open Access Publishing
232
ScholarsArchive@OSU (Oregon State University)
228
Université de Nantes: HAL-UNIV-NANTES
200
WikiBooks - Open-content textbooks
200
Oxford University Press (via Crossref)
194
LeibnizOpen (The Leibniz Association)
184
Institut national des sciences de l'Univers: HAL-INSU
182
University of California: eScholarship
177
ScienceDirect (Elsevier)
157
Informa
155
BioOne Online Journals
152
Cambridge University Press (via Crossref)
133
University of Michigan: Digital Collections
133
University of British Columbia: cIRcle - UBC's Information Repository
132
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server)
128
IODE-UNESCO: OceanDocs - E-Repository of Ocean Publications
117
International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC): Aquatic Commons
117
University of Lethbridge Digitized Collections
105
University of Tromsø: Septentrio Academic Publishing
104
more ...