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Tutorials: Boolean Searching

Boolean Searching

Library databases use Boolean search terms (a.k.a. operators) to combine keywords in database searches. The Boolean search terms use the words ANDORNOT to combine keywords and thus broaden or narrow your search results. Here are some examples of these operators:undefined

Using the Boolean search term AND will narrow your search results. In this case, using AND will retrieve search results containing both keywords globalization and human rights.

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Using the Boolean search term OR will broaden your search results. In this case, using OR will retrieve search results containing either the keywords globalization or human rights.

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Using the Boolean Operator NOT will narrow your search results. In this case, using NOT will retrieve search results containing the keyword globalization but will not retrieve search results containing the keyword human rights.

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Using the asterisk searches for any word that has Global as its truncation such as global, globalization, globalisation (UK Spelling), among others. 

Boolean search terms may help you narrow or expand the number of results you receive in a search.

For example, if you are writing a paper on birth defects, you may choose to search for:

"birth defects" - using the quotation marks tells the search engine that both words need to be together in the article, paper, video, etc. EACy Search returned 28,424 results using the search terms "birth defects".

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If you want to find resources that pertain to birth defects and downs syndrome, you may search for:

"birth defects" AND "downs syndrome". EACy Search returned 1,979 results for the search terms "birth defects" AND "downs syndrome". Using the word AND can help narrow your search to find only items that have both search terms.

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For results that display either birth defects or downs syndrome, try searching:

"birth defects" OR "downs syndrome". EACy Search returned 53, 349 results when searching for sources that contain either there terms "birth defects" or "down syndrome". Using the word OR helps to expand your search to include all terms you are researching. This can be especially helpful if your topic has several different terms such as "pro-choice" OR "abortion"; "assisted suicide" OR euthanasia, among other popular research topics.

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If you would like to exclude downs syndrome, search:

"birth defects" NOT "downs syndrome". EACy Search returned  26, 445 results for "birth defects" NOT "downs syndrome", and these results should provide information on birth defects, but not include downs syndrome.

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In summary, Boolean search terms, also known as Boolean operators, help students find the most relevant information quickly by narrowing the results or expanding them.

 

The word "AND" combines search terms and provides search results that have all of the search terms. Students have two options for using the Boolean Operator AND.

1) Students can enter the word AND directly in the search box as shown below.undefined

2) Students may use the Advanced Search option and enter the search terms separately and select the Boolean Operator from the dropdown menu as illustrated below.

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Both methods will return the same search results.

The word "OR" combines search terms and provides search results that have at least one of the search terms. Students have two options for using the Boolean Operator OR.

1) Students can enter the word OR directly in the search box as shown below.

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2) Students may use the Advanced Search option and enter the search terms separately and select the "NOT" Boolean Operator from the dropdown menu as illustrated below.

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Both methods will return the same search results.

The word "NOT" eliminates search terms and provides search results that have only the search terms you require because it eliminates the search terms following the word NOT. Students have two options for using the Boolean Operator NOT.

1) Students can enter the word NOT directly in the search box as shown below.

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2) Students may use the Advanced Search option and enter the search terms separately and select the "NOT" Boolean Operator from the dropdown menu as illustrated below.

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Both methods will return the same search results.

Using the * at the end of a search term allows the search engine to look for words associated with the truncation. For example, if the search below for child* AND disease, EACy Search looks for sources that have the terms:

  • child
  • children
  • childhood

AND

  • disease

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The use of truncated words allows the researcher to find sources that may use various forms of the root word and expand the number of results returned. If you have too many results, try different search terms or using the Boolean search terms to narrow your topic.

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