Medical Subject Headings (MeSH) are the building blocks for a good literature search in the Health Sciences. It is the controlled vocabulary developed by the National Library of Medicine since the late 1800's. In this tutorial you will learn how to access and to use the MeSH vocabulary to search for books in QCAT. In a subsequent medical information literacy class, we will build on this knowledge to search Ovid Medline and PubMed.

In order to conduct a subject heading search in QCAT you must know the subject heading used to describe the concept. One method of determining the appropriate MeSH term has already been discussed in the Search by Keyword section. A second option is to consult an online MeSH thesaurus or browser, which will be discussed in subsequent medical information literacy classes.

The most important reason to search QCAT using MeSH is that the MeSH is a controlled vocabulary. Searching with the controlled vocabulary you do not have to enter variant spellings and synonyms of concepts, as required when searching with keywords. For example, the appropriate MeSH term for allergy or allergies is "Hypersensitivity". Also, medical history has a MeSH term and it is "History of Medicine". The example highlighted in this section will be the MeSH term "History, Modern 1601-".

Below is the "History, Modern 1601-" tree. The tree structure shows how the subject headings fit into a hierarchy of broader and narrower terms. Additionally, it is a tool to help you determine the best MeSH term to use in your search strategy. More specific MeSH terms are indented under the "History, Modern 1601-" entry. This is the pattern for most medical subject headings.

• History, Modern 1601-
  • History, 17th Century
  • History, 18th Century
  • History, 19th Century
  • History, 20th Century
  • History, 21st Century

Important: A search conducted using the "History, Modern 1601-" term DOES NOT retrieve the items indexed with the narrower terms. Each MeSH term is unique and will retrieve different books. Because of the nature of books, broad subject headings are used most often to describe their content. However, starting a search with the broadest term first may bring numerous items in which the needed data is lost in too much information.

Subheadings can be used with MeSH terms to create specific search strategies. Subheadings are used to further describe a certain aspect of a disease, organism, drug, etc. In total there are 83 medical subheadings and some are listed below. Subheadings will be discussed in greater detail in a subequent medical information literacy class.

• adverse effects
• drug therapy
• rehabilitation
• surgery
• statistics

QCAT also permits the use of form subheadings. Form subheadings are used to describe the format of the material. Examples include:

• atlases
• biography
• essays
• exhibitions
• handbooks.

In QCAT the MeSH term and subheading combination would be entered as a search string (e.g. asthma diagnosis, neoplasms drug therapy handbooks). In the next section, you will search QCAT with MeSH terms.