Boolean Operators
Boolean operators define the relationships between words or groups of words.
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USE |
TO |
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AND, + |
Narrow search and retrieve records containing all of the words it separates. |
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OR , | |
Broaden search and retrieve records containing any of the words it separates. The | (Pipe) can be used in lieu of 'or', eg: mouse | mice | rat is equivalent to mouse or mice or rat |
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NOT , - |
Narrow search and retrieve records that do not contain the term following it. |
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( ) |
Group words or phrases when combining Boolean phrases and to show the order in which relationships should be considered, eg: (mouse or mice) and (gene or pseudogene) |
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Note: Search queries containing several operators search in the following order: |
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To ensure that a search containing different operators
performs as you intend, use parentheses, |
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Proximity Searching |
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Proximity searches limit the number of words between your search terms. |
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USE |
TO |
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no operator |
Find words as a phrase, eg: life stage transitions retrieves records containing the three words immediately adjacent to one another and in the same order. |
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WITHIN "X" |
Find words within a specified radius, eg: (women) within 5 (violence) retrieves records that contain women and violence in any order and within a five word radius of one other. Any number may be used to determine the proximity radius |
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NEAR |
Find words within 10 words of each other, eg: women near violence retrieves records that contain women and violence in any order with up to 9 words in between. Note: near is the same as within 10. |
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BEFORE |
Finds words in a relative order, eg: social before security. Note: adjacency is not implied. |
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AFTER |
Finds words that contain words in the relative order specified with the after expression, eg: scope after science. Note: adjacency is not implied. |
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Note: Use double quotes " " to search for "near", "before", or "after", eg: "near death" experience |
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Wildcard Symbols |
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Wildcard symbols can expand the scope of your search. |
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USE |
FOR |
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* |
Truncation. This expands a search term to include all forms of a root word, eg: patent* retrieves patent, patents, patentable, patented, etc. |
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* |
Multi-character wildcard for finding alternative spellings. Use to indicate an unlimited number of characters within a word, eg: h*ophilia retrieves haemophilia as well as hemophilia, and behavi*r retrieves behaviour or behavior. |
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? |
Single-character wildcard for finding alternative spellings. The ? represents a single character; two ?? represent two characters; three ??? represent three characters, and so on. Use within or at the end of a word, eg: wom?n finds woman as well as women, and carbon fib?? finds carbon fiber or carbon fibre. |
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Note: Only words with characters equal to the number of
?'s present are retrieved, eg: cell? retrieves cells and cello
but not cell. |
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Tip: When looking for singular and plural forms of short words that have a common root, such as cell, the truncation symbol may retrieve too many irrelevant words, while the wildcard symbol may retrieve too few words. In such a case, do not use wildcards and instead OR together the forms of the word you want, eg: cell or cells. |
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