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? A question mark is called a wild card. In a search, it replaces one character within a word.
* An asterisk is used for truncation. It is always placed at the end. It searches for all words that start with the root phrase before the pound sign. The * represents any number of letters at the end of the word.
These are Boolean operators.
Think of each keyword as having a "set" of results that are connected with it.
These sets can be combined to produce a different "set" of results.
AND is used to reveal only the documents that have both ​concepts.. Use AND to narrow your search.
For example. Below you see the difference in the amount of results that occurs by using the various operators.
The words "HIV' and 'Denialism will both be present in each record.
OR is a connector that allows either word to be present in each record in the results. Use OR to expand your search.
Either 'adolescents' or 'teenagers' (or both) will be present in each record.
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NOT is a connector that requires the first word be present in each record in the results, but only if the record does not contain the second word.
So a search for HIV AND Adolescents OR Teenagers NOT in the United States will remove records that include United States