By doing this, the result ‘black T-shirts and purple shoes for sale’ will not be returned. For example, use “black shoes” to get results where the words ‘black’ and ‘shoes’ appear together, eg ‘black shoes for sale’. Quotation marksĪlthough not strictly a Boolean operator, quotation marks can be used to get more accurate results. Some search engines use a minus sign in front of the word instead of NOT, eg -brown. The query ‘shoes NOT brown’ will return results that contain the word shoes but NOT the word brown. NOT tells a search engine what to ignore. The NOT operator is exclusionary it excludes specific search terms and so the query will not return any results with that term (or terms) in them. Most search engines would interpret this as ‘black OR white AND shoes’. Use OR to request an alternative, for example ‘black OR white shoes’. This won’t guarantee that the words will appear next to each other, only that both words will be present in results, eg ‘black T-shirts and purple shoes for sale’. NOT: Excludes certain keywords from your results. OR: Either of the keywords must appear in the results. These words have to be entered as capitals or they are not recognized as. There are three Boolean Operators: AND: All keywords must appear in your results. Operators are, for example, quotes or question marks, and the words AND, OR, and NOT. searching with AND, NOT, OR & NEAR (all capital) between two search terms can help refine your search. Sometimes you have to add AND to get results that contain both words. Using a Boolean Operator will tell the database to connect the terms together in your search. In general, search engines treat the query ‘black shoes’ as ‘black AND shoes’ - which means results must contain both words, eg ‘black shiny shoes for sale’. You may get results that contain only one of the two words, eg ‘purple shoes for sale’ or ‘black T-shirts for sale’. The words 'black' and 'shoes' will return results that contain the words 'black' and/or 'shoes'. They can be used to get more accurate search results. (see below, 4.The most common Boolean operators are AND, OR and NOT (always in capitals). (osteoporosis AND "Alzheimer’s disease") OR "Parkinson’s disease" Osteoporosis AND ("Alzheimer’s disease OR "Parkinson’s disease") Always check the parentheses after a search to be certain the database put them where you expected.That is, apple not w/20 pear is not the same as pear not w/20 apple. Databases generally have an order in which they process Boolean terms, but that order may differ between databases Use parentheses to change the processing order Unlike the W/ operator, NOT W/ is not symmetrical.Use a NOT operator to exclude terms from your search (see Example 3 below).The default in most databases is to combine the terms with the AND operator ("Ilene health 2015" becomes "Ilene AND health AND 2015").This operator is also helpful when a keyword has multiple meanings. The operators must be written in ALL CAPS (there may be exceptions, but this is good practice and helps you keep track of your search terms) The not operator prevents retrieval of documents in which specified terms occur together.Three Boolean operators are recognized by most databases: AND, OR, and NOT.Examples of each term and search strategy are given below. Boolean searching (named after George Boole) is used by most databases to focus searches.
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