Searching in PubMed

A guide for using PubMed, the world's largest database for biomedical and health sciences literature.

NCBI & NLM Documentation

NCBI Website and Data Usage Policies and Disclaimers
A General Introduction to the E-utilities
Overview including usage guidelines and requirements, E-utilities, frequency, timing and registration of E-utility URL Requests, demonstration programs and more.
New API Keys for the E-utilities
Reviews what an API key is and why you may want to use one.
NCBI APIs
Available APIs and access to documentation including an API for PubMed Central.
How to Use Web APIs for Text Mining
Chih-Hsuan Wei, Robert Leaman, Zhiyong Lu (2016). Beyond accuracy: Creating interoperable and s calable text mining web services, Bioinformatics, DOI:10.1093/bioinformatics/btv760.

About APIs

An API (Application Programming Interface) allows applications to talk to one another and can be used to facilitate downloading large amounts of data from a website. APIs are useful when you want to extract a large amount of data for text or data mining.

Introduction to APIs: Tutorial (~1:30)
Short, straightforward tutorial from Emily Chao and Berwin Xie of the Women in Computer Science (WCS) group at the University of Illinois at Urbana-Champaign Computer Science Department.
Using APIs Guide
Clear guidance from UC Berkeley's Engineering and Integration Services for how to work with APIs.

API Key Management

Create and manage an API key in the API Key Management section in your My NCBI Account Settings.

E-utils users are allowed 3 requests/second without an API key. Create an API key to increase your e-utils limit to 10 requests/second.

Contact the NCBI help department if you need to request higher throughput. Only one API Key per user. Replacing or deleting will inactivate the current key. Use this key by passing it with api_key=API_KEY parameter. Refer to additional documentation for more information.

API Support: eutilities@ncbi.nlm.nih.gov

Last Updated: Sep 2, 2025 11:35 AM
URL: https://libguides.ucmerced.edu/pubmed
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Tags: biomedical literature, health sciences, public health