Logical Operators, also known as Boolean, are more frequently and easily used to combine more than one search term.
AND
Use AND to narrow a search and retrieve records containing all of the words linked by it, e.g. adolescents AND children will only find records containing both these words.
OR
Use OR to broaden a search and retrieve records containing any of the words linked by it, e.g.adolescents OR children will find records containing adolescents only, children only, or both words.
NOT
Use NOT to narrow a search and retrieve records that contain the first term, but do not contain the term following it, e.g. adolescents NOT children will find records that contain adolescents, but will not contain the word children.
What's in this page:
SYSTEM SEARCH DEFAULTS
DEFAULT SETTINGS THAT CAN BE CHANGED:
* |
The asterisk (*) is the Truncation character, used to replace one or more characters. The truncation character can be used at the beginning (left-hand), end (right-hand), or in the middle of a word. The maximum number of characters that can be replaced is 10. Example: Searching for econom* will find economY, economICS, economICAL, etc. Limited truncation: a number can be entered next to the asterisk to define how extensive the truncation should be. Example: econom[*2] will find economY, economIC but not economIST, i.e. will replace up to 2 characters only An asterisk can also be used within the double quotes to account for the retrieval of plurals, for example. Example: "economic value*" can help retrieving also the plural "economic values" |
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? |
The question mark symbol (?) is the Wildcard character, used to replace any single character, either inside or at the left or right end of the word. Example: Searching for t?re will find tire, tyre, tore, etc. |
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- |
Use a hyphen to indicate a range when searching numerical fields, such as Publication date. Example: YR(2005-2008) |
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< > |
Use the less than or greater than symbols to indicate before/after or smaller/larger or less/more when searching numerical fields, such as the Publication date. Example: YR(>2008) will located documents published after 2008 |
Please Note: When using the asterisk (*) or wildcard (?) in your search, any terms retrieved using either or these are not considered when sorting your results based on relevance. This is because there is no way for ProQuest Dialog to assess the relevance of these terms to your research as the term itself is not exact. For example, your search on 'bio*' could return occurrences of any or all of these terms: 'bionic' or 'biosynthesis' or 'biodegrade' or 'biographic.' One, some, all, or none could be relevant to your search.
Proximity operators can be used in combination or in alternative to the Logical Operators to add precision to the search.
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NEAR/# OR N/# |
Finds documents where the search terms are separated by up to a max # of intervening words in any order. |
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PRE/# OR P/# |
Finds documents where the search terms are separated by up to a max # of intervening words in the specified order. Example: "business management" PRE/1 education business management high education |
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EXACT OR .e |
Used primarily for searching specific fields, like Subject, EXACT looks for your exact search term in its entirety, rather than as part of a larger term. Example: EXACT(“higher education”) in the Subject field |
Please note: PRE and NEAR will always be considered operators. If they need to be processed as search terms, must be put between double quotes.
"NEAR" P/1 THE P/0 RIVER will retrieve the phrase NEAR THE LARGE RIVER
NEAR THE RIVER will generate an error message saying: We can't interpret your search. Invalid use of a search operator.
The Dialog search system assumes your search terms should be combined in a certain order. If you include operators such as AND and OR in the same search string, the system will combine them in this order: PRE, NEAR, AND, OR, NOT.
This order can be changed putting terms between parentheses, which means that the complete order of preference is actually:
For instance, a search like this: dog OR cat AND food OR nutrition
will retrieve a certain number of documents which contain both CAT and FOOD, plus a certain number of documents which may contain either DOG or NUTRITION alone, thus including several potentially irrelevant documents
Parentheses can be used to control the order in which the search terms are combined, instead of using the standard operator precedence.
Considering the precedence order, the above search will be processed this way: dog OR (cat AND food) OR nutrition
In order to get the intended results, i.e. documents that contain either DOG or CAT, but also must contain either FOOD or NUTRITION, in any combination, use the parentheses to change the order: (dog or cat) AND (food or nutrition)
More precision can be added to the search by limiting the search terms to specific fields, such as Title, Author, Publication Title, Publication Date, etc by which the records are broken down (indexed).
The Search Field drop down menu in Advanced Search can be the first help in finding which are the search fields for a given database.
For Command Line search the search using fields follows this syntax:
FIELDLABEL(search term)
Eg. TI(ALONG THE RIVER)
to search in the Title field
For even more in depth information refer to the ProSheets, the PQDialog database guides.