Boolean operators are search tools that allow you to provide specific limits on the types of results returned to you. If you’ve ever Googled something, you have already used Boolean searches. Even if you’ve used it without realizing it, you can learn a few Boolean operators that will drastically improve your search results
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​Important Note: When using Boolean operators, please ensure that they are written in all caps (e.g., AND, OR, NOT) to function properly. Our backend Elasticsearch workflows are case-sensitive, and using lowercase or mixed case operators may yield significantly different results.

AND

Narrow your search results to include only relevant results that contain your required keywords

Example: (Alzheimer’s AND target)

The above example will only yield documents that have both of those keywords.

OR

Expands your search results so all results must contain at least one, if not more, of your defined keywords or phrases.

OR is useful for two scenarios.

NOT

Limits your search by excluding defined keywords and/or phrases from your results.

Example: drug NOT vitamin

The above search reveals all results that discuss drugs, excluding those that also mention "vitamin".

"Quotation Marks"

Use quotes around a phrase that needs to be returned in that exact order.

For example, "United States of America" will yield results with that exact term, but without quotes, each word in the phrase will be treated separately, as if you used OR between each word (United OR States OR of OR America).

(Parenthesis)

Parentheses are used to give priority to the keywords contained within over the other elements around it. As a rule of thumb, parentheses should be used around OR statements, ensuring the search engine properly resolves the OR statement before moving on to other operators.

For example, (Tumor OR Carcinoma OR Cancer) AND treatment will yield results that mention treatment and any one or several of the key terms in parenthesis.

Asterisks*

* on a term matches multiple characters preceding a stem.

For example, hydroxych* yields results for hydroxychloroquine, hydroxycholesterol, etc.

Question Mark?

? on a term that matches a single character preceding a stem.

For example, a?duction can yield results for abduction and adduction.

Another example can be anemi? to find results for anemia and anemic.