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.
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The and operator specifies two terms that must be included. |
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The not operator specifies a term that must be excluded. |
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The or operator specifies that at least one expression or term in an expression is |
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Entering terms in quotation marks creates a bound phrase that specifies a side-by-side |
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Entering terms and operators in parentheses creates an expression that functions |
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Boolean Operator: AND
The and operator returns any combination of the terms' plurals, synonyms, or alternate spellings.
Example: The query flavor and aroma returns only results that contain plurals/synonyms/alternate spellings of both terms.
Entering terms in quotation marks to create a bound phrase narrows the term to include.
Example: The query "flavor" and "aroma" returns only results that contain the exact spelling (includes plurals) of both terms.
Entering terms in parentheses to create an expression expands the number of terms to include.
Example: The query ("flavor" or "aroma") and "turmeric" returns only results that contain flavor(s), aroma(s), or both and turmeric.
Boolean Operator: NOT
The not operator excludes any combination of the terms' plurals, synonyms, or alternate spellings.
Example: The query flavor not dye returns results that contain plurals/synonyms/alternate spellings of flavor but excludes those that contain plurals/synonyms/alternate spellings of both flavor and dye.
Entering terms in quotation marks to create a bound phrase narrows the term to exclude.
Example: The query "flavor" not "dye" returns results that contain flavor(s) but excludes those that contain both flavor(s) and dye(s).
Entering terms in parentheses to create an expression expands the number of terms to exclude.
Example: The query (turmeric or aroma) not (dye or flavor) returns results that contain plurals/synonyms/alternate spellings of turmeric or aroma, but excludes those that also contain plurals/synonyms/alternate spellings of dye or flavor.
Boolean Operator: OR
Most often used with within parentheses in Boolean expressions, the or operator is technically interpreted as at least one term/phrase/expression is required, more than one or all can be returned.
Example: The query ("flavor" or "aroma") and ("turmeric" or "curcumin") returns only results that contain flavor(s), aroma(s), or both and turmeric, curcumin, or both.
Note: Results containing both terms/phrases/expressions are scored higher than results containing only one.
Boolean Modifier: " "
Enclosing terms within quotation marks creates a bound phrase, which means that:
- Term(s) must appear side-by-side as they do within the quotes (not case sensitive).
- Plural spellings are matched, but excludes alternative spellings and synonyms (e.g.,"extract" matches extract and extracts but not extracting).
For example, the query “cortisol metabolites” AND “GnRH agonist” will only return results that have both of the exact bound phrases. Results with any of the following would be ignored:
- cortisol and amino acid metabolites (terms separate, not side by side)
- LHRH agonist (synonym of GnRH agonist)
- corticosterone metabolites (synonym of cortisol)
Note: The AND operator is implied when searching for two sequential terms or phrases within quotes. For example, the query "pain treatment" "headache disorders" is searched as "pain treatment" AND "headache disorders".
Boolean Modifier: ( )
Enclosing terms and a Boolean operator within parentheses creates a Boolean expression that functions as a single unit/condition that can interact with other terms, expressions, phrases, and operators.
Example: The query (aroma not flavor) and ("turmeric" or "curcumin") returns only results that contain plurals/synonyms/alternate spellings of aroma, but not plurals/synonyms/alternate spellings of flavor and also contain turmeric, curcumin, or both.