Tutorials: MEDLINE: MEDLINE Ultimate

MEDLINE: Searching Using MeSH

MeSH (medical subject headings) is the National Library of Medicine's controlled vocabulary thesaurus. Each bibliographic reference is associated with a set of MeSH terms assigned to describe the content of an article. There are more than 19,000 main headings in MeSH, as well as thousands of cross-references that assist in finding the most appropriate MeSH headings. MeSH terms are arranged in a hierarchy, or "tree structure," that permits searching at various levels of detail, from the most general to more narrow levels, to find the most precise terms. Subject specialists at the National Library of Medicine update MeSH annually.

MeSH records include indexing annotations, scope notes, entry vocabulary, history notes, and allowable qualifiers. MeSH headings can be exploded to retrieve all references indexed to the term, as well as all references indexed to any narrower term(s). Searches can be limited to Major Headings where MeSH headings indicate the main focus of an article. Searches can also be qualified with specific subheadings, to improve the precision of a search.

MEDLINE Complete: Using Clinical Queries

You can refine your search using specific search strategies designed to narrow your results in nine research areas: Therapy, Diagnosis, Prognosis, Reviews, Clinical Prediction Guides, Qualitative, Causation (Etiology), Costs, and Economics.

Three strategies are provided for each area:

• High Sensitivity - the broadest search to include ALL relevant material. It may include less relevant materials.
• High Specificity - the most targeted search to include only the most relevant result set, may miss some relevant materials.
• Best Balance - retrieves the best balance between Sensitivity and Specificity.