Many medical databases have an official, authorised, and highly structured set of subject headings - also known as a thesaurus - which are used to describe the content of journal articles.

The best known of these thesauri is MeSH - Medical Subject Headings: this is used in MEDLINE and PubMed, and other databases including the Cochrane Library, and JBI COnNECT+.

CINAHL has its own set of subject headings - CINAHL Headings.

In the health sciences, a search using the thesaurus is probably the best type of search you can do. But it's important to check what the subject headings are. CINAHL makes this easier for you by offering a "Suggest subject terms" feature. See below for more.

If you do search using CINAHL Headings, it's usually best to do this by one search idea at a time, and combine the search sets later using Search History.

In CINAHL Plus with Full Text, you can search or browse the CINAHL Headings, or you can get the database to "suggest subject terms".

To search or browse CINAHL Headings, click on the link and follow the prompts.

To match your topic or idea to subject terms, enter your topic/idea/concept in the first search box, tick the box for "Suggest subject terms", and click on Search.

Let's use decubitus ulcers as an example. If you search the CINAHL Headings for items that contain the phrase decubitus ulcers, or if you ask the database to suggest subject terms for decubitus ulcers, you get a match for Pressure Ulcer, as shown on the headings results screen:

Clearly, the suggested CINAHL Heading (subject term) for decubitus ulcers is Pressure Ulcer.

From here, there are different ways in which you can proceed ...

1. If you tick the box for Pressure Ulcer, you are presented with a list of subheadings. The default is to Include all Subheadings, but you can narrow your choice to one or more. If you choose more than one subheading, the database will combine these with the OR operator. The idea is to work across the screen from left to right. Your selection(s) appear in the Search Term box, and you click on Search Database to actually search for articles.

Note that you are given the option to search for your original terms as a keyword. If you choose the original term (decubitus ulcers) as well as the suggested CINAHL Heading (Pressure Ulcer), the search will combine these with the OR operator.

2. If, rather than tick the box for Pressure Ulcer, you actually click on the subject heading itself, you are taken into the tree view of the subject headings - that is, the subject heading hierarchy. This can be a help because you can see broader terms and narrower terms, which you might choose to use instead. Here, the broader term is Skin Ulcer, and there are two narrower terms. Deep Tissue Injury, and Heel Ulcer.

At this screen, you can proceed to search for one subject heading or a combination of subject headings.

You can also:

• tick the Explode box to select, and search for, not only that subject heading but also any narrower terms that appear beneath it in the hierarchy. This is a way of broadening your search. The plus sign against a subject heading indicates that there are narrower terms. Here, if you tick the Explode box for Pressure Ulcer, you will get all articles that include that as a subject heading, plus all articles that have Deep Tissue Injury, or Heel Ulcer, as a subject heading.
• tick the Major Concept box to search only for articles where that subject heading appears as a Major Subject Heading. This is a way of narrowing your search to return only articles where that topic is the main focus of the article. (If you can't remember what a Major Subject Heading is, go back to the screen-shot in the box on Searching Using Different Fields.]

Once again you work from left to right, with your selection(s) appearing in the Search Term box, and you finish the process by clicking on Search Database.