| 1 | Arxiv: database of Physics |
| 2 | AGRIS: Agricultural Database |
| 3 | Analytical Science Digital Library (ASDL) |
| 4 | Anthropological Index Online (Bibliographical database) |
| 5 | Arnetminer (Online service used to index and search academic social networks) |
| 6 | Astrophysics Data System (Astrophysics, Geophysics, Physics) |
| 7 | BASE: Bielefeld Academic Search Engine (Multidisciplinary) |
| 8 | Bioinformatic Harvester |
| 9 | ChemXSeer: database of Chemistry |
| 10 | CHBD: Circumpolar Health Bibliographic Database (Medicine) |
| 11 | CiteSeerX (Science) |
| 12 | CogPrints: Cognitive Sciences Eprint Archives |
| 13 | CERN Document Server |
| 14 | EconBiz |
| 15 | ERIC: Educational Resource Information Center |
| 16 | GENESIS (Women’s history, Feminism) |
| 17 | SciTech Connect: Department of Energy Scientific and Technical Information |
| 18 | Intute (Social sciences and Humanities) |
| 19 | Mendeley (Multidisciplinary) |
| 20 | eSocialscience (Social Sciences) |
| 21 | OAIster (Multidisciplinary) |
| 22 | OpenGray (Multidisciplinary) |
| 23 | PhilPapers |
| 24 | POPLINE (Population,Family Planning,Reproductive Health) |
| 25 | PubChem (Chemistry) |
| 26 | PubPsych (Psychology) |
| 27 | RePEc: Research Papers in Economics |
| 28 | SafetyLit (Injury prevention literature) |
| 29 | gov (Physical sciences) |
| 30 | SSRN: Social Science Research Network |
| 31 | SPIRES-HEP |
| 32 | WorldWideScience |
