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Health: CINAHL Searching

What is the Difference?

Review vs. peer review vs. research

  • Peer review, as a subject, refers to the process of doing peer review
  • Peer review, as a limit in CINAHL, finds articles in peer reviewed journals
  • Review is used when an author searches the literature on a specific topic and then writes a summary (or review) of what they’ve learned
  • Research. as a limit in CINAHL, is a type of publication used for research based articles as opposed to practice/clinical based articles


Subheadings are qualifiers used in conjunction with subject headings. There are 68 topical subheadings that can be linked to CINAHL subject headings. Examples of subheadings are: adverse effects, diagnosis, or prevention and control.

Not all subheadings can be used with all subject headings; for example, the subheading "/prevention and control" is meaningless linked to the subject heading NURSING PROTOCOLS.

A listing of all subheadings available, plus publication types, and special interest options is provided in the PDF document.

Subject Headings

CINAHL subject headings reflect the terminology used by nurses and allied health professionals.

Subject headings are a set of terms or phrases (known as controlled vocabulary) that classify materials. Essentially they identify and pull together under a common "umbrella" information about a given subject. Most online catalogs and databases use some form of subject headings, though they may also be called descriptors or keywords.

The set of controlled vocabulary used to index and search PubMed is called MeSH (MEdical Subject Headings). NLM indexers examine articles and assign the most specific MeSH heading(s) that appropriately describes the concept(s) discussed.

  • The indexer will assign as many MeSH headings as appropriate to cover the topics of the article (generally 5 to 15).
  • When there is no specific heading for a concept, the indexer will use the closest, general heading available.

Indexers can also assign Subheadings to further describe a particular aspect of a MeSH concept (more information on this topic is in the next column.)

In addition to assigning MeSH terms that describe the topic of the article, the indexer provides terms that reflect:

  • characteristics of the group being studied (e.g., the age group, human or other animal, male or female)
  • the material represented (Publication Types) e.g., Clinical Trials, Editorial, Review

The MeSH terms that reflect the major ideas of the article are marked with an asterisk (*).


  • CINAHL Subject Headings are arranged in a hierarchy.
  • The "explode" feature lets you select the term, plus any terms indented underneath it.
  • In the figure to the right, exploding Face would search face as well as every subject indented underneath this primary subject. Exploding Eye would search eye or eyelids or eyelashes.
  • If a term has a + next to it, then it also has a set of "children" terms. These will also be included in the explode.
  • Check the explode box  - as indicated in the next image,  it is the first column to the right of the subjects, to search for all indented/narrower subjects:
  • explode
  • Rule of Thumb: ALWAYS EXPLODE!!
  • Major concept can always be used - whether Explode is used or not.  See below for more on using Major Concept.

Major Concept

Subject headings can also be restricted to the Major Concept of the article. Selecting Major Concept allows you to restrict your results to articles in which the subject heading is the main idea of the article. 

  • Major Concept and Explode can both be checked.  This will return results that include the indented, more narrow concepts when those subjects are the major focus of the article.
  • Rule of Thumb: Use Major Concept SPARINGLY or NOT AT ALL!
    Every term can't be the main idea; you will miss good articles if you use this feature with every term.


MeSH subjects are organized by 16 main branches:

  1. Anatomy
  2. Organisms
  3. Diseases
  4. Chemical and Drugs
  5. etc.

This example displays part of the hierarchy that includes the term, Face. Notice the narrower terms indented under the broader terms.

Image of Tree view for subjects concerning the face

Click on the subject word (rather than the box next to the subject) to open the Tree view.