November 22, 2005 [Editor's note added]
PubMed® Subject Searching Avoids Conflicts with Journal Titles
[Editor's Note: This feature was implemented in PubMed on September 20, 2005.]
PubMed optimizes searches using a process known as Automatic Term Mapping (ATM). ATM compares terms from the search query with lists of terms: MeSH® (including Unified Medical Language System® (UMLS®) mappings), journal titles, and author names.
If a searcher's query includes untagged terms that are not found in the MeSH translation table, the mapping process continues to the next table, the Journals translation table. If the terms match a full journal title, a title abbreviation, or an ISSN number in the Journals translation table, then the journal is searched in PubMed. This recognition of journal names works well for the vast majority of journals, e.g., Annals of Internal Medicine and The American Journal of Cardiology; however, sometimes a subject search contains terms that happen to match a full journal name. A search for brain development, for example, translates to "Brain Dev"[Journal].
To prevent some subject searches from mapping to journal searches, an exceptions table is used for terms that have a conflict. Terms on this table are searched as subjects rather than as journals. Currently, there are three terms in the exceptions table: heart failure, pediatric surgery and treatment review.
A search for heart failure translates to:
("heart"[MeSH Terms] OR heart[Text Word]) AND failure[All Fields]
A search for pediatric surgery translates to:
(("surgery"[MeSH Subheading] OR "surgery"[MeSH Terms]) OR surgery[Text Word]) AND pediatric[All Fields]
And, a search for treatment review translates to:
("therapy"[Subheading] OR ("therapeutics"[TIAB] NOT Medline[SB]) OR "therapeutics"[MeSH Terms] OR treatment[Text Word]) AND ("review"[Publication Type] OR "review"[Text Word])
Without the exceptions table, these terms would map to the journals, i.e., Heart Failure, Pediatric Surgery, Treatment Review.
The exceptions table is being expanded so that other subjects are not searched as journals as the default. Examples of terms to be added are: abdominal surgery, brain development, early pregnancy, pain medicine, and virus genes.
Again, most journal searches are not affected by the exceptions table. Check Details to see how your search has been translated by PubMed. To ensure a journal search is performed, use the Journals Database, the Citation Matcher, the title abbreviation, e.g., brain dev, or the journal tag [ta] with the full name of the journal, e.g., brain development [ta].
For more information about Automatic Term Mapping, see PubMed's Help.
McGhee M. PubMed® Subject Searching Avoids Conflicts with Journal Titles. NLM Tech Bull. 2005 Sep-Oct;(346):e3.