NASA Astrophysics Data System (ADS)

NASA Astrophysics Data System (ADS) compared with Google Scholar, Scopus and INSPIRE HEP
NASA Astrophysics Data System (ADS)	Google Scholar	Scopus	INSPIRE HEP
Field coverage: ADS is specialised in astronomy, planetary science and physics, and it also indexes arXiv e-prints. It is the reference index for space science rather than a general database.	Field coverage: Google Scholar aims to cover all fields of research, all languages and all countries. Breadth is the goal, so it has no particular depth in astrophysics.	Field coverage: Scopus is a source-neutral database divided into 27 major subject areas and more than 300 minor ones. Physical sciences are one of four title clusters, next to social, health and life sciences.	Field coverage: INSPIRE covers high energy physics only. It is the focused counterpart for particle physics, as ADS is for astronomy.
Indexed content: ADS lists journals, conference proceedings and some NASA reports, plus observing proposals from Chandra, HST and IUE. Abstracts for the period from about 1975 to mid-1995 came from the NASA STI group, and Crossref metadata has been used since 2007.	Indexed content: Google Scholar indexes articles, theses, books, abstracts and court opinions. A page is included only if the full text or the full author abstract is freely visible, so paywalled pages may be represented only by metadata.	Indexed content: Scopus holds about 26,600 active peer-reviewed journals, over 11.7 million conference papers, over 292,000 books and over 49.2 million patent records from five patent offices. Book reviews and conference meeting abstracts are excluded.	Indexed content: INSPIRE holds over 1.7 million literature records (March 2025). It also maintains directories of people (HEPNames), institutions, conferences, jobs and experiments, and it extracts plots from papers.
Citations and profiles: ADS citation and reference lists cover a defined subset of records and time spans, so counts are not complete. Users can save record lists in private libraries.	Citations and profiles: Google Scholar lets you explore citations and related works and check who cites your own publications. Updates to existing papers can take 6 to 9 months to appear.	Citations and profiles: Scopus offers citation count, Field-Weighted Citation Impact and citation benchmarking, with references going back to 1970 for most content. It has about 17.6 million author profiles with author identifiers that can link to ORCID.	Citations and profiles: INSPIRE provides citation metrics and crowdsourced author disambiguation. Its author directory is a separate, curated service for the HEP community.
Programmatic access: ADS can be queried through an API with a personal token generated in the account settings, and requests count against a daily rate limit. Python clients exist for it.			Programmatic access: INSPIRE has a read-only REST API that returns JSON by default and can return BibTeX and LaTeX citation formats for literature records. Each IP address is limited to 15 requests in a 5-second window.
Access model: ADS links to the full text where it is available online, but access is often restricted by the publishers. Abstracts and articles remain under publisher copyright.	Access model: Google Scholar helps you locate the complete document through your library or on the web. Whether you can read it depends on the publisher.	Access model: Scopus is available for organization subscription access only. A free Scopus Preview shows which titles are indexed and some metrics.	Access model: INSPIRE gives free public access and is built on Invenio, an open source digital library platform. It is run by a collaboration of CERN, DESY, IN2P3, IHEP, SLAC, Fermilab and TIB, and replaced SPIRES in 2012.

NASA Astrophysics Data System (ADS) compared with Google Scholar, Scopus and INSPIRE HEP

NASA Astrophysics Data System (ADS)

Google Scholar

Scopus

INSPIRE HEP

Field coverage: ADS is specialised in astronomy, planetary science and physics, and it also indexes arXiv e-prints. It is the reference index for space science rather than a general database.

Field coverage: Google Scholar aims to cover all fields of research, all languages and all countries. Breadth is the goal, so it has no particular depth in astrophysics.

Field coverage: Scopus is a source-neutral database divided into 27 major subject areas and more than 300 minor ones. Physical sciences are one of four title clusters, next to social, health and life sciences.

Field coverage: INSPIRE covers high energy physics only. It is the focused counterpart for particle physics, as ADS is for astronomy.

Indexed content: ADS lists journals, conference proceedings and some NASA reports, plus observing proposals from Chandra, HST and IUE. Abstracts for the period from about 1975 to mid-1995 came from the NASA STI group, and Crossref metadata has been used since 2007.

Indexed content: Google Scholar indexes articles, theses, books, abstracts and court opinions. A page is included only if the full text or the full author abstract is freely visible, so paywalled pages may be represented only by metadata.

Indexed content: Scopus holds about 26,600 active peer-reviewed journals, over 11.7 million conference papers, over 292,000 books and over 49.2 million patent records from five patent offices. Book reviews and conference meeting abstracts are excluded.

Indexed content: INSPIRE holds over 1.7 million literature records (March 2025). It also maintains directories of people (HEPNames), institutions, conferences, jobs and experiments, and it extracts plots from papers.

Citations and profiles: ADS citation and reference lists cover a defined subset of records and time spans, so counts are not complete. Users can save record lists in private libraries.

Citations and profiles: Google Scholar lets you explore citations and related works and check who cites your own publications. Updates to existing papers can take 6 to 9 months to appear.

Citations and profiles: Scopus offers citation count, Field-Weighted Citation Impact and citation benchmarking, with references going back to 1970 for most content. It has about 17.6 million author profiles with author identifiers that can link to ORCID.

Citations and profiles: INSPIRE provides citation metrics and crowdsourced author disambiguation. Its author directory is a separate, curated service for the HEP community.

Programmatic access: ADS can be queried through an API with a personal token generated in the account settings, and requests count against a daily rate limit. Python clients exist for it.

Programmatic access: INSPIRE has a read-only REST API that returns JSON by default and can return BibTeX and LaTeX citation formats for literature records. Each IP address is limited to 15 requests in a 5-second window.

Access model: ADS links to the full text where it is available online, but access is often restricted by the publishers. Abstracts and articles remain under publisher copyright.

Access model: Google Scholar helps you locate the complete document through your library or on the web. Whether you can read it depends on the publisher.

Access model: Scopus is available for organization subscription access only. A free Scopus Preview shows which titles are indexed and some metrics.

Access model: INSPIRE gives free public access and is built on Invenio, an open source digital library platform. It is run by a collaboration of CERN, DESY, IN2P3, IHEP, SLAC, Fermilab and TIB, and replaced SPIRES in 2012.