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	PubMed och MEDLINE	Scopus-databasen	Ulrichsweb Global Serials Directory
Ämnesområde	Bibliometri	Bibliometri	Bibliometri
Familj	Process / pipeline	Process / pipeline	Process / pipeline
Ursprungsår	1966	2004	1932
Upphovsperson	National Library of Medicine (NLM), U.S. National Institutes of Health	Elsevier	Bowker (originally R.R. Bowker), now ProQuest LLC
Typ	Database	Database	Database
Ursprungskälla	National Library of Medicine. (2024). PubMed: Home. Retrieved from https://pubmed.ncbi.nlm.nih.gov/	Elsevier. (2024). Scopus: The largest abstract and citation database of peer-reviewed literature. Retrieved from https://www.elsevier.com/products/scopus	ProQuest. (2024). Ulrichsweb: Global Serials Directory. Retrieved from https://ulrichsweb.serialssolutions.com/
Alias	PubMed, MEDLINE, NLM, PubMed Central	Scopus, Elsevier Scopus	Ulrichsweb, Ulrich's International Periodicals Directory, Ulrich's Directory
Närliggande	5	5	4
Sammanfattning	PubMed is a free, publicly accessible literature database maintained by the National Library of Medicine (NLM), a division of the U.S. National Institutes of Health. It provides access to biomedical and life sciences literature from MEDLINE (the curated subset of ~30 million indexed journal articles), life science journals, in-process articles, and preprints. MEDLINE, established in 1966, is the gold standard for biomedical literature indexing, using MeSH (Medical Subject Headings), a hierarchical controlled vocabulary of ~33,000 terms. PubMed is the primary discovery tool for clinicians, researchers, and healthcare professionals worldwide seeking evidence-based information.	Scopus, owned by Elsevier, is the world's largest abstract and citation database covering peer-reviewed journals, conference proceedings, and book chapters across all scientific disciplines. Launched in 2004, Scopus now indexes over 37 million documents from more than 6,500 journals, with expanded coverage of open-access publications and emerging regional journals. Scopus provides researchers and institutions with comprehensive citation tracking, field-normalized impact metrics (CiteScore, SJR, SNIP), and analytical tools for literature discovery, research evaluation, and institutional benchmarking.	Ulrichsweb is a comprehensive, subscription-based global serials directory cataloging over 300,000 print and electronic journals, magazines, newspapers, and other periodical publications. Developed by ProQuest (originally R.R. Bowker), Ulrichsweb has served librarians and researchers for over 90 years as the authoritative source for journal metadata, publication information, and peer-review verification. A unique feature is Ulrichsweb's verification program: editorial staff contact journals directly to confirm peer-review claims, marking journals as 'refereed' only after validation. This verification process distinguishes legitimate peer-reviewed journals from predatory publishers falsely claiming peer review.