1. Boolean Operators
Boolean operators (OR, AND, NOT) allow you to link terms together, either to widen a search or to exclude terms from your search results.
| OR |
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Use to broaden your search, increasing the number of references retrieved. Use "OR" to search for synonyms and related terms for each concept within a research question. For example, when searching for the concept "exercise based rehabilitation" you might use the following terms: rehabilitation OR exercise OR exercise therapy OR sports OR exertion OR physical training OR aerobics OR kinesiotherapy |
| AND |  |
Used to narrow a search, therefore decreasing the number of references. For example, searching for: Would retrieve just those references covering both topics. |
| NOT |  |
Used to narrow a search, therefore decreasing the number of references. dogs NOT sheep Would retrieve references dealing with females, but not those which discuss males. Caution should be exercised when using NOT, In the example above, research dealing with both dogs and sheep would be excluded from the search results. |
Proximity (sometimes called “adjacency”) searching is similar to using Boolean operators in that you are specifying relationships between 2 or more terms. However, proximity searching allows you to specify the proximity of words to each other. Some databases allow you to search for words within a specified number of words from each other. This feature is not available in PubMed.
For example you can use NEAR/n or NEXT/n:
drug* NEAR/2 adverse means the words must be within n words inclusive of each other in the record.
adverse NEXT/2 reaction* means he words must be within n words inclusive of each other in the same order as they appear in the search form.
| ADJACENCY |
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Nest search terms to control the logic of your search. For example:
(rehabilitation OR exercise OR exercise therapy OR sports OR physical training) AND (Coronary heart bypass OR myocardial ischemia OR myocardial infarction OR coronary disease OR coronary thrombosis)
