PubMed.gov is a freely-accessible web-based interface and database providing searchable access to more than ~28 million citations in the bio-medical literature, dating back to the 1940s (with some content back to the 19th century). PubMed's core is MEDLINE, the premier index to the medical journal literature, which is developed at the National Library of Medicine. Medline indexes ~5900 journals published in 70 countries from 1966 to present.
Unique content in PubMed
PubMed has some unique content that you will not find in MEDLINE. Some of its other unique features are:
In-process citations with records for articles before MeSH indexing, added to MEDLINE or converted as out-of-scope status
Today's current citations that are in process for MEDLINE indexing (when supplied electronically by publisher)
Out-of-scope citations (e.g., plate tectonics, astrophysics) from some journals, primarily in science and chemistry for which life sciences articles are indexed for MEDLINE; links to articles in BookShelf
Some life science journals that submit full text to PubMed Central and may not have been recommended for inclusion in MEDLINE although they have undergone a review by NLM, and some physics journals that were part of a prototype PubMed in the early 1990s
In 2014, NLM began adding citations 7 days a week. More than 806,000 citations were added to MEDLINE in 2016
PubMed is just one of a number of search tools used to access MEDLINE. The National Library of Medicine leases MEDLINE information to private vendors such as OVID Technologies, EBSCO and SilverPlatter. To reiterate, MEDLINE is the core of PubMed, and an idea of how to use MeSH vocabulary is essential for effective searching of the database.
IndexCat contains over 4.5 million references to over 3.7 million bibliographic items dating from over five centuries and covering subjects of the basic sciences, scientific research, civilian and military medicine, public health, and hospital administration. A wide range of materials can be discovered through IndexCat, including books, journal articles, dissertations, pamphlets, reports, newspaper clippings, case studies, obituary notices, letters, portraits, as well as rare books and manuscripts. Recently, two new collections, involving medieval scientific English and Latin texts, were made available through IndexCat. Opening a new frontier in historical research, these additional collections encompass over 42,000 records of incipits, or the beginning words of a medieval manuscript or early printed book. IndexCat users can search incipit data by manuscript, library, author/translator, title, subject, date and other information.
The History of Medicine Division of the National Library of Medicine creates the IndexCat database, which is the online version of the Index Catalogue of the Library of the Surgeon-General's Office.
The question about the amount of Canadian content in PubMed is an important one. True, PubMed may appear to have an American bias, but this may be because of several factors related to where journals are published and where clinicians work. However, to determine how much Canadian content resides in a database, searchers should consider that there are Medical Subject Headings (MeSH) that permit the application of terms for all provinces and territories. Use Canada or Canadian as keywords, for example. Specific health issues regarding Canada's health care systems are not well-addressed by PubMed and there is an inherent American bias (as mentioned) in the controlled vocabulary. Geographic subdivisions - Canada, and the provinces - are recommended for health issues pertaining to specific regions of the country ie. HIV infection in the downtown Eastside of Vancouver, try "British Columbia" or "Canada"[MeSH] and "downtown eastside" (or its variants). See alsoAboriginal health search filter.