Reference Search Boolean Operators and Modifiers

Use Boolean search operators and modifiers to target your search query and to find the results you need faster.

For example, a references search for turmeric immune cells returns over 11 million results; focusing the query by adding the and operator and quotation marks to search turmeric and "immune cells" returns 124 results.

The and operator specifies two terms that must be included.

Examples:

  • flavor and extract

  • 3463-67-7 and 7664-41-7

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The not operator specifies a term that must be excluded.

Examples:

  • electrolysis not haptens  

  • 1,5-Di-2-naphthalenyl-3-pentanone not Dibenzylideneacetone

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The or operator specifies that at least one expression or term in an expression is required, more than one or all can be returned.

Examples:

  • ("flavor" or "extract") and ("turmeric" or "curcumin")

  • (flavor not dye) or extract

  • 13463-67-7 or 7664-41-7

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Entering terms in quotation marks creates a bound phrase that specifies a side-by-side relationship and an exact spelling (matches plurals, but excludes alternative spellings and synonyms).

Examples:

  • cortisol metabolites and GnRH agonist

  • acetic anhydride not nitrogen nucleophiles

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Entering terms and operators in parentheses creates an expression that functions as a single unit that interacts with other terms.

Examples:

  • (extract not flavor) and ("turmeric" or "curcumin")

  • ((turmeric or flavonoids) and immune cells) not inflammatory

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