Content Provider
DataCite Metadata Store (German National Library of Science and Technology)
73,722
Directory of Open Access Journals: DOAJ Articles
56,407
PANGAEA - Data Publisher for Earth & Environmental Science
21,511
Unknown
16,802
Arctic Data Center (via DataONE)
12,766
Springer Nature (via Crossref)
6,594
Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center)
5,284
University of Calgary Journal Hosting
4,991
Arctic Institute of North America
4,889
Arctic Council Repository
4,198
ScienceDirect (Elsevier - via Crossref)
4,180
Wiley Online Library
4,080
PubMed Central (PMC)
3,986
DataCite
3,890
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe)
3,859
Defense Technical Information Center: DTIC Technical Reports database
3,556
Open Parks Network
3,531
Informa (via Crossref)
3,529
Cambridge University Press
3,527
Copernicus Publications: E-Journals
3,507
LeibnizOpen (The Leibniz Association)
3,317
Informa
3,316
Zenodo
2,897
ScienceDirect (Elsevier)
2,859
University of Tromsø: Munin Open Research Archive
2,649
Springer Nature
2,633
Aarhus University: Research
2,558
Université de Nantes: HAL-UNIV-NANTES
2,274
Niedersächsisches Online-Archiv NOA
2,262
Institut national des sciences de l'Univers: HAL-INSU
2,228
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel)
2,014
MDPI Open Access Publishing
1,991
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy)
1,937
CyberLeninka (Scientific Electronic Library)
1,746
University of Copenhagen: Research
1,718
NOAA NCEI Environmental Data Archive (via DataONE)
1,701
LaCRIS - University of Lapland Current Research System
1,569
David Rumsey Historical Map Collection (Cartography Associates)
1,517
Dryad Digital Repository (Duke University)
1,382
RePEc (Research Papers in Economics)
1,325
Hathi Trust Digital Library
1,249
IOP Publishing
1,246
University of Wisconsin, Milwaukee: UWM Libraries Digital Collections
1,194
University of Michigan: Digital Collections
1,182
University of California: eScholarship
1,139
Natural Environment Research Council: NERC Open Research Archive
1,130
Biodiversity Heritage Library (BHL)
1,111
JSTOR (via Crossref)
1,082
University of Washington, Seattle: Digital Collections
1,071
NASA Technical Reports Server (NTRS)
1,047
more ...