simultaneous searching of a general (“broader”) subject heading and the more specific (“narrower”) subject headings which fall under it. For example, if you “explode” the term 'infant', you will also retrieve the more specific terms, 'infant, newborn', 'infant, premature' and more. Without explode, you would retrieve only the broader term itself and not any of the more specific terms that might have been assigned by the indexer. Explode utilizes the automatic OR' ing together of a MeSH term and the narrower terms associated with it.
permits simultaneous searching of both a broad subject and the narrower subjects classed under it (e.g., searching "Antiviral Agents" will retrieve articles on antiviral agents in general, new antiviral agents not yet assigned a MeSH heading, plus individual drugs such as "Acyclovir" or Zidovudine" classed as antiviral agents in Medline). Because indexing norms require that the most specific subject heading available be applied, normally an article indexed under the specific heading would not also be indexed under the broader heading; thus, searching only the broad subject would result in lost references which have been indexed under the more specific heading.
A Boolean operation that calculates the OR (union) of a given word and all its narrower terms. If the end user chooses to explode a term, the selected term and all of its narrower terms are returned.