Searching with Subject Headings

Several databases in the Science, Technology and Medicine (STEM) subject areas offer subject heading searching
You may also hear this technique described as MeSH (medical subject headings), thesaurus, indexed terms, descriptors or controlled vocabulary searching

NB: this is not the same as searching for a keyword within the text of articles - see the section on Freetext searching for more information.

Why use a Subject Heading or Thesaurus term?

Where a Subject Heading is available, this offers a powerful method for picking up all relevant material related to your subject, for two reasons:

One:

Indexers at the database providers allocate subject headings to the articles
This means that a lot of the cross referencing has been done, and historical terms and alternatives brought together under one term

Two:

Subject headings form part of a hierarchy or 'subject tree'
This enables you to view the structure of the literature and to take decisions on whether to broaden or narrow your search

Medical Subject Heading (MeSH) in Ovid Medline

The image below shows the term Blood transfusion:

Subject heading in Medline with scope option

On the right is the Scope note ('i') - select this to find out more about the term and its coverage
Include all subheadings - tick this box, unless you are only looking for a precise aspect of the topic (eg: 'pathology', 'education')

You can also choose to 'explode' your search (tick-box on the right):

This enables a fuller search including your general term plus all of its narrower terms
For example, Blood Transfusion can be 'exploded' to include the narrower headings such as 'Blood component transfusion', 'Blood transfusion, autologous' and others. See below:

Subject tree for MeSH Blood transfusion

Engineering Thesaurus Entry in Compendex Database

Compendex, for Engineering, has a similar system of broader, narrower and related terms in its Controlled Term search facility.

Searching for Concrete produces a range of options in an A-Z list: choosing one then triggers a search using that term

Compendex controlled search term Concrete with list and results on screen

On the list of results on the main screen, there should also be filters on the left to further Refine the search, including Controlled Vocabulary. Results produced by searching "Concrete" include further vocabulary options such as "Roads and streets", "Beams and girders".

Controlled vocabulary Refine options under Concrete

NB: where this is no exact match for the subject heading you require, you may need to combine one or more subject headings, and/or rely on keyword/free text searching instead.

Combining subject headings:

You can combine the terms you find using the Boolean operators AND, OR, NOT. These should usually be on separate lines in your search history: combine these lines as required.

See the guide to Effective Search Techniques on "Using Boolean and other Search Operators".

Notes:

Please see the following Library Guides for more information:

Effective Search Techniques
Literature searching for MDS (Medical and Dental Sciences and related subjects)
Databases for Engineers

See also the Canvas course 'Systematic Literature Searching' on the Academic Skills Gateway, University of Birmingham under Research Skills - Finding and using resources.

Screenshots of Compendex and Ovid Medline courtesy of Elsevier and LWW Wolters Kluwer respectively: databases subscribed under license to University of Birmingham.

Other images above purchased from iStockPhotos for use by the University of Birmingham.