Sometimes just combining search terms (keywords) with the standard Boolean ‘AND’ operator is not granular enough to focus results in to retrieve relevant articles. Typically, in addition to Boolean Operators and double quotes for exact phrases, many databases also allow specifying that the keywords searched be within a certain number of words of each other in either direction. This bridge between the narrow exact phrase search and the broad ‘AND’ operator search is called Proximity or Adjacency searching and it uses Proximity, or Adjacency, operators. Proximity searching is not applicable to searching with subject headings, it is applicable to keyword searching only. Proximity operators help increasing specificity of the search. Typically, in complex search strategies, both Proximity and Boolean operators are used.
Proximity searching is available in major proprietary databases, including Embase, Scopus, CINAHL, Web of Science, and databases on OVID platform, such as Medline and PsycINFO. Proximity searching is not available in Pubmed.
Proximity operators and rules for using them vary by database.
An example of Proximity Operators in Embase:
The databases specific Proximity Operators and the rules for their use can be found in the Help pages for each database.