Searching OpenAlex

This doc describes how to use Boolean search to retrieve records from OpenAlex via Application Program Interface (API).

What is OpenAlex? #

OpenAlex is a free, open index of scholarly literature. It covers a broad range of research disciplines and is continuously updated as new publications are indexed. In Nested Knowledge, you can query OpenAlex directly the same way you would on openalex.org, and searches can be scheduled to re-run automatically so your Nest stays current over time.

Entering a Boolean Query #

Boolean Operators can be used to specify the structure of your search.

Basic Boolean Operators #

When entering your search terms of interest, use:

• AND / OR / NOT to separate terms,
• quotation marks to search for an exact phrase, and
• parentheses to dictate groupings and priority order

to narrow in on publications of interest. For example,

(diabetes OR obesity) AND "cardiovascular disease" AND "randomized controlled trial"

will retrieve all OpenAlex-indexed publications that contain all of the following in their title, abstract, or keywords:

• The word diabetes or the word obesity
• The exact phrase cardiovascular disease
• The exact phrase randomized controlled trial

Note: Boolean operators must be capitalized (AND, OR, NOT). Lowercase versions will not be interpreted as operators.

Tips for Searching OpenAlex #

Stemming #

OpenAlex automatically applies stemming, meaning different word forms of the same root are treated as equivalent. You do not need to add every variant of a term manually.

• studies will also return results containing study or studying
• fish will also match fishing or fisheries

Stop-Words #

Common stop-words — such as the, a, in, and of — are ignored in queries. Including or excluding them makes no difference to your results.

• "effects of sleep" is treated identically to "effects sleep"

Note: this behavior differs from PubMed, where stop-words in quoted phrases are preserved. Keep this in mind if copying a query between databases.

Using Concept and Topic Tags #

OpenAlex automatically assigns concept and topic tags to works based on its internal taxonomy. Filtering by concept ensures broad coverage of an entire subfield without needing to enumerate every possible synonym.

• Example: concept:"cardiovascular disease" — captures all subtopics under cardiovascular research

Combining Search and Filters #

Broad keyword queries can be refined using filters on publication date, open access status, or full-text availability. Filters are applied alongside your keyword query string.

Filter by Date #

Restrict results to a specific publication date range:

• Example: from_publication_date:2020-01-01

Filter by Open Access Status #

Restrict results to open access publications only:

• Example: is_oa:true

Filter by Full Text Availability #

Restrict results to works with a full text available:

• Example: has_fulltext:true

Filters can be combined with keyword queries. For example, diabetes AND alzheimer's filtered to from_publication_date:2020-01-01 and is_oa:true will return only open access studies on both conditions published from 2020 onward.

Guidance on Search Creation #

See also our guidance on the following search creation tips, which apply across PubMed, EuropePMC, and OpenAlex:

• PICO
• Expanding or Narrowing?
• How many records is “enough,” and when to stop?
• OpenAlex Quickstart Tutorial