> For the complete documentation index, see [llms.txt](https://citemed-io.gitbook.io/citemed.io-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://citemed-io.gitbook.io/citemed.io-documentation/advanced-topics/search-term-syntax-and-errors.md).

# Search Term Syntax and Errors

#### Intro

This guide will help you build search queries for all the major databases we offer.

#### PubMed

Reference Link: <https://pubmed.ncbi.nlm.nih.gov/help/>

#### PubMed Central

[User-guide reference link](https://www.ncbi.nlm.nih.gov/pmc/about/userguide/#search)

#### Cochrane

[CochraneQRG Search syntax.pdf](https://prod-files-secure.s3.us-west-2.amazonaws.com/403a01b1-682f-4f98-a66d-d38465b55214/315823c5-a525-491c-8205-60cf2e3f387f/CochraneQRG_Search_syntax.pdf)

#### [ClinicalTrials.gov](http://ClinicalTrials.gov)

<https://classic.clinicaltrials.gov/api/gui/ref/syntax#andExpr>

Notes:

* ( ) not permitted on these.
* AND OR NOT statements permitted