MeSH on Demand identifies MeSH Terms in your text using the NLM Medical Text Indexer (MTI) program. After processing, MeSH on Demand returns a list of MeSH Terms relevant to your text as well as a list of related articles from PubMed.

LitCovid is a curated literature hub for tracking up-to-date scientific information about the 2019 novel Coronavirus. The articles are updated daily and are further categorized by different research topics (e.g. Long Covid) and geographic locations for improved access.

Open-i service provides search and retrieval of abstracts and images (including charts, graphs, clinical images, etc.) from the open source literature, and biomedical image collections. Searching may be done by text queries as well as by query images.

Not all articles in PMC are available for text mining and other reuse, many have copyright protection, however articles in the PMC Open Access Subset are made available for download under a Creative Commons or similar license that generally allows more liberal redistribution and reuse than a traditional copyrighted work.

NLM produces bibliographic records for books, journals and other materials from NLM's collections in NLMXML, MARCXML and MARC 21 formats. These records can be searched at NLM LocatorPlus or the NLM Catalog.

PubMed Central (PMC) is a free, digital archive of full text biomedical and life sciences journal literature.

PubMed is a free resource supporting the search and retrieval of biomedical and life sciences literature with the aim of improving health–both globally and personally.

The PubMed database contains citations and abstracts of biomedical literature. It does not include full text journal articles; however, links to the full text are often present when available from other sources, such as the publisher's website or PubMed Central (PMC).

See the PubMed User Guide for more information. https://pubmed.ncbi.nlm.nih.gov/help/

Information about abstracts with distinct, labeled sections (e.g., Introduction, Methods, Results, discussion) that appear in MEDLINE.

The List of Serials Indexed for Online Users (LSIOU) provides bibliographic information for all journals whose articles were ever indexed over time with the MeSH® vocabulary and cited in MEDLINE®, the backbone of the NLM PubMed® database. It includes titles that ceased publication, changed titles, or are no longer indexed. More detailed bibliographic data and information about indexing coverage for serials cited in MEDLINE/PubMed can be found in LocatorPlus Catalog®, the NLM online catalog, and the NLM Catalog, an Entrez database.

The OLDMEDLINE subset in PubMed® represents journal article citations from two print indexes: Cumulated Index Medicus (CIM) and the Current List of Medical Literature (CLML). Created by the National Library of Medicine® (NLM®), there are approximately 2,011,000 article citations from international biomedical journals that cover the fields of medicine, preclinical sciences and allied health sciences from 1946 through 1965. OLDMEDLINE records, which are included in the MEDLINE® database, can be searched via PubMed.

The OLDMEDLINE subset in PubMed contains citations from the 1960 through 1965 Cumulated Index Medicus (CIM) print indexes and the 1946 through 1959 Current List of Medical Literature (CLML) print indexes. The OLDMEDLINE subset does not include citations from the Quarterly Cumulative Index Medicus (QCIM) print indexes. A hand search of the QCIM print indexes is necessary to ensure comprehensive review of medical periodical literature of the world from 1946 through 1956.