2. ResearchGate – researchgate.net
3. Academia.edu – academia.edu
4. CORE – core.ac.uk
5. Semantic Scholar – semanticscholar.org
6. PubMed Central – ncbi.nlm.nih.gov/pmc
7. arXiv – arxiv.org
8. SSRN – ssrn.com
9. JSTOR (Free Access) – jstor.org
10. SpringerOpen – springeropen.com
11. DOAJ (Directory of Open Access Journals) – doaj.org
12. EThOS (British Library Theses Service) – ethos.bl.uk
13. Unpaywall – unpaywall.org
14. ScienceOpen – scienceopen.com
15. OpenAIRE – openaire.eu
16. OSF Preprints – osf.io/preprints
17. PaperPanda – paperpanda.app
18. Bielefeld Academic Search Engine (BASE) – base-search.net
19. ERIC (Education Resources Information Center) – eric.ed.gov
20. Citationsy Archives – citationsy.com/archives
21. DeepDyve – deepdyve.com
22. PLOS (Public Library of Science) – plos.org
23. Zenodo – zenodo.org
24. bioRxiv & medRxiv – biorxiv.org | medrxiv.org
25. PsyArXiv – psyarxiv.com
26. PhilPapers+ – philpapers.org
27. HAL Archives – hal.archives-ouvertes.fr
28. Redalyc – redalyc.org
29. SciELO (Scientific Electronic Library Online) – scielo.org
30. WorldWideScience – worldwidescience.org
31. Research4Life – research4life.org
32. Hindawi Publishing – hindawi.com
33. MDPI Open Access – mdpi.com
34. Cambridge Open Engage – cambridge.org/engage
35. Wiley Open Access – wileyopenaccess.com
36. Nature Communications – nature.com/ncomms
37. EBSCO Open Dissertations – opendissertations.com
38. OATD (Open Access Theses & Dissertations) – oatd.org
39. Digital Commons Network – network.bepress.com
40. Internet Archive (Scholar Section) – https://lnkd.in/gv7TBdQN
https://www.irc.nic.in/index1.aspx?lsid=231&lev=2&lid=221&langid=1
https://www.worldcat.org/search?q=n2%3A2320-7590&qt=advanced&dblist=638