Searching with a Thesarus
Thesauri come in all forms. Some, like PubMed, are in the form of a hierarchy tree and it is easy to see which are the broader (more general) and the narrower (more specific) terms. Other, like in EBSCO, put the terms in a list and label them "broader" and "narrower". Some, as with many ProQuest databases, include both options. Terms are seldom the same across thesauri as each thesaurus focuses on the materials within its own database.
The Heirarchy
Example of a Thesaurus hierarchy tree (from PubMed)
- Selected term: Climatic processes
- Broader term: Ecological and environmental phenomena
- Narrower terms: Air movements, Cyclonic storms, etc.
Within a thesaurus, you may also see:
- Notes / Scope Note: Description of the selected term used by indexers when deciding whether or not to apply it to a citation - Check this to be sure the database looks at a term the same way you do
- Previous Indexing: Terms that are no longer used (are not current) - but you may need to use these terms to search for older citations (dates of indexing are usually included)
- Qualifiers / Subheadings: Focused concepts that may be applied to a selected term (e.g. therapy to cancer, diagnosis to a disease, etc.)
- Related terms / See also: Similar terms, but not contained within the hierarchy tree you have selected
- Use / Use for: Use this selected term for terms that are not (or are no longer) in the Thesaurus
When a database automatically maps search terms to thesaurus terms (e.g. PubMed), you may see:
- Entry Terms: Terms used by a searcher that are specifically mapped to the selected term
Searching Tips
Searching with a Thesaurus
- Move up the tree to find more general search terms and move down the tree to identify more specific terms
- Select a term, often with a check box, and add it to your search
- Use Boolean operators to focus the search (Recommended: when searching for multiple narrower terms, OR them together)
- When appropriate, add qualifiers or subheadings to focus on a specific aspect of your search term (e.g., cancer surgery, dementia etiology)
Search options may include:
- Explode: Include all narrower terms when searching for the selected term
- Major: Select citations where the indexer has indicated this topic (or its narrower term) is the major focus of the citation
Additional Heirarchy Examples
ProQuest Hierarchy Tree (for MeSH 2017 Thesaurus) with Candy as the selected term.
Not all ProQuest indexed databases have hierarchy trees. When available, the selected term may be clicked a second time.
OmniFile Thesaurus entry with Coin-Operated machines as the selected term.
In this case, the original search term was "juke" and I moved up the tree through Jukeboxes to the above selected term.
Example of a Scope Note (OmniFile Full Text Mega)
