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Researching for your literature review: 6. Activity: Subject searching

Subject searching in Ovid Medline

An Ovid Medline record in the Complete Reference format is shown below. Note the list of MeSH subject headings assigned to the article.

Medline complete reference






Medline MeSH subject headings

Activity: Search by subject heading

Key databases such as Ovid Medline allow you to do a subject heading search to locate relevant subject headings for your key concepts.

1.  Login to Ovid Medline at

2.  Enter healthcare workers, tick the Map Term to Subject Heading box, and click Search.

search example

Your search term is mapped to a Medical Subject Heading (MeSH) if possible. Healthcare workers is not a subject heading that is used in this database, however Health personnel is suggested as a relevant subject heading.

Click on the Scope note  Scope note next to Health personnel for more details including a definition of this term. Note the list of synonyms under Used for. After confirming it is appropriate for your topic, click on the link for this subject heading.

Subject heading

The subject heading tree is displayed. Look for any relevant narrower or broader terms for Health Personnel and select all that apply. If you want to select all narrower terms, tick the Explode button. In this case we will do this.

subject heading in tree

Then scroll to the top of the page to click Continue. A list of subheadings is displayed. Select Include All Subheadings, and click Continue for a comprehensive search.


3.  Enter communication, ensure the Map Term to Subject Heading box is ticked, and click Search.

search example

Communication is listed as a subject heading. Notice that Health Communication is another heading. Click on the Scope note for further information. This is a relevant subject heading so make a note to include it in the next search. Click on the link for the subject heading Communication.

subject heading in tree

A section of the subject heading tree is displayed. Note the more specific (or narrower) terms listed underneath Communication. Narrower terms will not be automatically included in your search if they are not individually ticked, or if the explode box of the broader term is not ticked. Tick Nonverbal Communication and Manual Communication. Then click Continue.

4.  Now search for the heading Health Communication. There are no narrower terms so click Continue. A list of subheadings is displayed. Select Include All Subheadings, and click Continue for a comprehensive search.


5.  Enter hearing disability, ensure the Map Term to Subject Heading box is ticked, and click Search.

search example

There are several relevant subject headings suggested, including Hearing Disorders, Hearing Loss and Deafness. Look at the Scope notes for more information. Make a note of the relevant headings. Click Hearing Disorders to look at it in the tree. 

Note that a narrower term of Hearing Disorders is Hearing Loss. Click the plus sign to look at narrower terms for Hearing Loss.

subject heading tree

Now you can see that Deafness and a range of other narrower terms are displayed. In this case we will tick the broader term Hearing Disorders, As well as Exploding the term Hearing Loss to include Deafness and other narrower terms. 

explode subject heading

Scroll to the top of the page and click Continue.

6.  Go to the Search history and combine any results related to the same concept with OR

search history

Then combine all the search sets from each concept with AND

search history

Now you will be able to see the final number of search results from this search. Scroll down to see the search results displayed or apply any Limits.

search history

7.  Tick the English language limit, and then click Search. This limits the last search result in the Search History. There are many more limits available if you click on the Additional limits button.


8.  Review your results and refine your search if necessary. Note that the results are listed in order from newest to oldest (not relevance).

Tip: For articles that are very relevant to your topic ensure you look at the Complete reference in Ovid Medline to see which MeSH have been applied to the article. You may find relevant MeSH that you can add to your own search strategy.

Understanding subject headings

In some databases the records are tagged with subject headings which are chosen from a defined list and describe the content of the article.

Looking at the subject headings in a database record may suggest potential search terms relevant for your search strategy.

In the biomedical sciences, subject heading searching is a particularly important step in capturing all of the research evidence.

Because of the branching structure of the subject heading hierarchies, these lists are sometimes referred to as trees

In Medline each record is tagged with MeSH (Medical Subject Headings).

If you explode a subject heading you will retrieve all of the narrower, more specific subject headings that sit below it on the tree.

If you focus a subject heading you limit your search to only those documents in which your subject heading is considered the major point of the article. This is not recommended for comprehensive searches.

Subheadings are terms (sometimes called qualifiers) used with Medical Subject Headings.

Subject headings are not available for every topic and it is best to only select them if they relate closely to your research question. To determine this, look at the Scope Note which provides a definition of the subject heading.