An open-access search engine that indexes scholarly articles across disciplines and formats. Widely used to increase article visibility and citations.

A national indexing and citation system managed by the Indonesian Ministry of Education, Culture, Research, and Technology.  

A global research database providing access to publications, citation data, research grants, and patents.  

A DOI registration agency that ensures persistent linking and reliable metadata for scholarly publications.

An international database that evaluates journals and assigns the ICV (Index Copernicus Value) to reflect their scientific quality.

Harvard Library’s unified catalog (HOLLIS), providing a single search of books, articles, media, and other resources.

Boston University’s unified library search is a catalog system (Primo) that indexes books, journals, multimedia, and digital resources across its collections.

Leiden University’s unified library discovery system that indexes books, journals, digital materials, and other resources across its collections.

University of Texas’s unified library discovery is a catalog system that indexes books, articles, multimedia, and digital resources across its collection.

Bucknell University’s subject-based research catalog that indexes journals, articles, and resources by academic discipline.

BASE (Bielefeld Academic Search Engine) is a multidisciplinary academic search engine operated by Bielefeld University Library that indexes metadata from institutional repositories, digital collections, and scholarly web resources, offering open access to a large portion of its content.

An international directory managed by the ISSN International Centre that indexes open access scholarly resources, including journals, conference proceedings, and repositories.

An academic indexing database by ResearchBib that lists scholarly journals, articles, and conferences across disciplines, supporting visibility and accessibility of research.

WorldCat is a global library catalog that indexes books, journals, multimedia, and digital resources held by thousands of libraries worldwide.

An AI-powered academic search engine that indexes over 200 million scholarly papers, extracting meaning and connections to help researchers discover and understand relevant literature.