Literature searching and finding evidence

A more advanced way of searching than only using keywords is to use Subject Headings.

What are Subject Headings?

Each document within a database is categorised according to the topic(s) it covers and these categorisations are referred to as 'Subject Headings'.

Different databases use their own Subject Headings.

Medline and PubMed use 'MeSH terms': MeSH stands for 'Medical Subject Headings' and these are the terms created by the National Library of Medicine.

What is the advantage of using Subject Headings?

Keyword searches only look for the exact word you enter, not the context; therefore, a search for the word 'stroke' on its own might also pick up articles relating to 'pet therapy' or 'heat stroke'. That's why you need to combine 'stroke' with other keywords like 'adults' and 'treatment' to retrieve more relevant results.

A Subject Heading search will retrieve results where the focus of the study relates to the specific term selected; therefore, a Subject Heading search for a term related to 'stroke' should retrieve articles on the specific medical condition.

Searching using Subject Headings

As with a keyword search, you would need to search for Subject Headings related to each concept of your topic.

For example, for a topic on how exercise can reduce obesity in children, you would need to perform three separate Subject Heading searches on 'exercise', 'obesity' and 'children'.

Combining with a keyword search

For a more comprehensive search, combine a Subject Heading search with a keyword search. This is because:

• A study may have been categorised using different Subject Headings than the terms you used
• A Subject Heading may have been mistakenly left out of an article
• Subject Headings are different in each database, so you might not always find a relevant term to select.