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Advanced Searching with CINAHL® Subject Headings

The CINAHL Subject search allows researchers to build one-line simple or complex searches while using EBSCO’s many searching features. In CINAHL®, it is possible to incorporate CINAHL® Headings and Free Floating Headings in command line searches (searches that incorporate field codes).

What are Subject Headings?

The CINAHL® Subject Headings authority file is a controlled vocabulary thesaurus that assists in more effectively searching your CINAHL database. Each bibliographic reference in the database is associated with a set of subject terms that are assigned to describe the content of an article.

Note: Pre-CINAHL® databases do not yet have subject headings assigned.

CINAHL® subject headings terms are arranged in a hierarchy, or "tree structure", that permits searching at various levels of detail from the most general level to more narrow levels to find the most precise terms. The subject headings include indexing annotations, scope notes, entry vocabulary , history notes, and allowable subheadings. The subject headings can be exploded to retrieve all references indexed to that term as well as all references indexed to any narrower term(s). Searches can also be limited with specific qualifiers (subheadings) to improve the precision of the search, and limited to major subject headings, which indicate the main focus of an article.

What are Free Floating Subheadings?

Not all subheadings are valid with all Subject Headings.

Subheadings can be searched independently of the Subject Headings by using the appropriate two letter code in the word-indexed CINAHL® search fields (MW and MJ). If you wish to associate subheadings that are not valid with a given Descriptor, you may ‘AND’ the Descriptor and a Free Floating Subheading.

Ex. MW Bicycles AND MW “SU” to retrieve surgical treatment of bicycle related injuries.

Referencing the Database Help File

As you begin command line searching in your CINAHL® database, you may want to review the Database Help File for your CINAHL® database, as an excellent resource for further information. To locate your Database Help File, open to the search page of your CINAHL® database. To the right of the Find field, next to the Search button, you will see a blue circle containing a question mark bubble. Click on this question mark to open the Help File in a new window. Scroll to the bottom of the menu on the left side of the Help file and click on the CINAHL® database name under Database Help.

Using Headings in Command Line Searching
  • Subject Heading Searching

    As with all fields it is possible to search a subject heading using the selected subject heading field code and the CINAHL® subject heading.

    MH - Search the exact CINAHL® subject heading; searches both major and minor headings

    MM - Searches the exact CINAHL® subject heading; searches just for major headings


    1. To search for all citations indexed with the CINAHL® subject heading of Tennis Elbow, search for:

      MH “tennis elbow”

    2. To search for all citations indexed with CINAHL® major subject heading of Tennis Elbow, search for:

      MM “tennis elbow”

  • Subject Heading Searching with Subheadings

    It is possible to search a subject heading and use subheadings. (Note: CINAHL® subheading two letter codes are used and are available in Database Help.)

    To search for a subject heading with subheadings (in this example Tennis Elbow with Rehabilitation as a subheading), search for:

    MH “tennis elbow/rh”

    To search for a subject heading with multiple subheadings (in this example Tennis Elbows with subheadings of rehabilitation, nursing, therapy), search for:

    MH “tennis elbow/rh/nu/th”

  • Subject Heading Searching with Explosions

    It is possible to ‘explode’ a subject heading; use the + symbol

    To explode a subject heading, search for:

    MH “arm injuries+”

    To explode a subject heading with subheadings, search for:

    MH “arm injuries+/rh/nu”

  • Free Floating Subheadings

    CINAHL® subheadings can be searched independently of a subject heading. The appropriate two letter subject heading field code must be selected, as well as the two letter code for the desired subheading.

    You may locate subheading field codes in the Database Help File.

    MW – Searches for a word in the CINAHL® subject heading, including subheadings, retrieves citations indexed under major or minor.

    If the searcher wishes to find citations that are indexed with the subheading of adverse effects, and does not care to which CINAHL® subject heading it is attached, search for:

    MW “ae”


  • Field tags (such as MM, MW, etc.) must be entered in upper case.

  • The subject heading and accompanying subheadings MUST be placed in double quotes “” whenever there is a Boolean operator included in the CINAHL® subject heading. Example: The subject heading of “Bone and Bones” must be enclosed in quotation marks.

  • Be sure to include Free Floating Subheading codes in quotes so that the system will not try to interpret your code as a search field tag.