Content Provider
USGS Science Data Catalog (via DataONE)
895
University of Michigan: Digital Collections
433
APS Digital Library (American Philosophical Society)
385
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy)
383
DataCite Metadata Store (German National Library of Science and Technology)
375
Hathi Trust Digital Library
276
Biodiversity Heritage Library (BHL)
266
NOAA NCEI Environmental Data Archive (via DataONE)
262
University of North Texas: UNT Digital Library
245
The Library of Congress: American Memory
240
Research Workspace (via DataONE)
234
The University of Winnipeg: WinnSpace Repository
175
Zenodo
173
University of Washington, Seattle: Digital Collections
172
The Portal to Texas History (University of North Texas)
166
Open Parks Network
162
University of Lethbridge Digitized Collections
159
University of Calgary Journal Hosting
140
Unknown
136
Memorial University of Newfoundland: Digital Archives Initiative (DAI)
111
The Seattle Public Library Special Collections Online
111
Oklahoma State University: Digital Collections @ OKSTATE Library
110
LeibnizOpen (The Leibniz Association)
83
Defense Technical Information Center: DTIC Technical Reports database
68
Arca (BC's Digital Treasures)
60
SFU Digitized Collections (Simon Fraser University)
55
Directory of Open Access Journals: DOAJ Articles
54
New Mexico Digital Collections (The University of New Mexico - UNM)
51
UNBC's Digital Institutional Repository (University of Northern British Columbia)
46
PRISM - University of Calgary Digital Repository
40
Theses Canada/Thèses Canada (Library and Archives Canada)
40
The Online Books Page (Penn Libraries, University of Pennsylvania)
39
David Rumsey Historical Map Collection (Cartography Associates)
36
University of California: eScholarship
36
Washington State University: WSU Libraries Digital Collections
35
York University Digital Library
35
PANGAEA - Data Publisher for Earth & Environmental Science
34
Australian National University: ANU Digital Collections
33
Arctic Data Center (via DataONE)
32
Cambridge University Press
31
OhioLINK: Ohio Digital Resource Commons (DRC)
25
Wilfrid Laurier University, Ontario: Scholars Commons@Laurier
24
Project Gutenberg (PG)
22
University of Wisconsin, Milwaukee: UWM Libraries Digital Collections
22
AAAS Resource Center (American Association for the Advancement of Science - via Crossref)
21
American Museum of Natural History: AMNH scientific publications
21
University of British Columbia: cIRcle - UBC's Information Repository
21
Gulf of Mexico Research Initiative (via DataONE)
20
Harvard University: Harvard Collections
19
McGill University: eScholarship@McGill
19
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