Monday, April 18, 2005

Proximity Operators [Amended April 24, 2005]

Many search interfaces support proximity operators as well as the Boolean operators AND, OR and NOT. Proximity operators allow you to search for words occurring in the same part of the record or no more than a certain distance apart or with a certain frequency.

Each database will support different proximity operators and more importantly, will define them differently so before you use any make sure you know what you're doing.

Examples of proximity operators are: NEAR, ADJACENCY, SAME, WITH, FREQUENCY
And here's a few definitions:

Ovid: ADJ (adjacency) and FREQ (frequency)
  • ADJ retrieves records that contain both terms, in order, and adjacent in the same sentence. [blood clot - adjacency is the default operator; blood adj2 clot$ - retrieves records that contain both terms, in any order, with two words between]
  • FREQ retrieves records that contain n occurrences of the term in the specified field. [ blood.ab./freq=5 - retrieves records containing the word "blood," at least five times in the Abstract (ab) field].
Web of Science : SAME
  • SAME operator and the definition says that all terms separated by SAME must appear in the same subfield. [laser* SAME gas finds records containing laser or lasers and gas in the title, the same sentence in the abstract, or the same keyword phrase.]
Where do you find this information? In the HELP, of course!

Ovid supports AND, OR, NOT, ADJ, FREQ
Web of Knowledge supports AND, OR, NOT, SAME
Silverplatter (WebSPIRS) supports AND, OR, NOT, ADJ, NEAR, WITH
PubMed supports AND, OR, NOT


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