• Google Scholar (citation tracking and indexing)
• Index Copernicus
• OpenAlex (open scholarly metadata platform)
• Semantic Scholar (AI-driven academic search engine)
• Dimensions (research analytics and citation database)
• Scilit (MDPI scientific database)
• Scite (smart citation analysis platform)
• Zenodo (open-access repository and archiving)

Academic Networks and Research Platforms

• Mendeley (Elsevier research network)
• SSRN (Social Science Research Network)
• Academia.edu (academic sharing platform)
• R Discovery (AI-based research discovery tool)
• SciSpace (research reading and analysis platform)

Library Systems and Global Catalogs

• WorldCat (OCLC global library catalog)
• Swisscovery (Swiss academic library network)
• Technical University of Denmark Library
• HAW Hamburg Library
• ISTINA (Moscow State University academic system)

Identifiers, Registries, and Open Science Infrastructure

• Crossref (DOI registration and citation linking)
• ISSN International Centre
• OpenAIRE (European open science infrastructure)

Regional and Specialized Indexes

• Izdanii.ru (Russian academic indexing platform)

Research Access and Knowledge Initiatives

• Research4Life (HINARI programme)
• AccessON (open-access discovery support)
• Archive.org (digital preservation and archiving)