Search operators AND, OR, NOT, NEAR, and SAME may be used to combine terms in order to broaden or narrow retrieval.
Keep in mind that case does not matter when using search operators. For example, OR, Or, and or returns the same results. We use all uppercase in our examples as a matter of style.
Note: The Korean Journal Database does not include the SAME operator as a search operator.
Use AND to find records containing all terms separated by the operator.
Use OR to find records containing any of the terms separated by the operator.
Use NOT to exclude records containing certain words from your search.
Use NEAR/x to find records where the terms joined by the operator are within a specified number of words of each other.
Replace the x with a number to specify the maximum number of words that separate the terms.
If you use NEAR without /x, the system will find records where the terms joined by NEAR are within 15 words of each other. For example, these searches are equivalent:
Be aware that ...
You cannot use the AND operator in queries that include the NEAR operator. For example, the following query is not valid:
However, the NEAR operator may be used to find a word or phrase within X number of words of a phrase. The following queries are valid:
NEAR/0 dictates that the words joined by the operator should be adjacent.
When the Word NEAR Appears in a Title
Always enclose the word NEAR in quotation marks ( " " ) when the word appears in the title of a source item such as a journal, book, proceeding, or other type of work. For example, the following is a valid query.
If you leave out the quotation marks, the system returns an error message that states: "Search Error: Invalid use of NEAR operator"
Search Operator Precedence
If you use different operators in your search, the search is processed according to this order of precedence:
Use parentheses to override operator precedence. For example:
Use of Parentheses
Use parentheses to override operator precedence. The expression inside the parentheses is executed first.
(cadmium AND gill*) NOT Pisces finds records containing both cadmium and gill (or gills), but excludes records containing the word Pisces.
(salmon OR pike) NEAR/10 virus find records containing salmon or pike within 10 words of virus.
Beverage AND bottle finds records containing both terms.
Beverage AND bottle AND beer finds records containing all three terms.
Implied AND Operator
The product uses an implicit AND operator when you enter two or more adjacent terms in most fields.
For example, the title search rainbow trout fish farm is equivalent to rainbow AND trout AND fish AND farm -- both queries return the same number of results.
Note: Implied AND does not apply to Chinese-language search queries.
Beverage OR bottle finds records containing either beverage or bottle (or both).
Beverage NOT bottle finds records containing beverage but excludes records containing bottle.
Beverage NEAR/5 bottle finds records containing both beverage and bottle. The two words must be within five words of each other.