How can I improve my thesaurus search?
Last updated on March 26, 2026
Thesauri are guides to the controlled vocabulary used to index articles for Engineering Village. Thesauri are hierarchical, organizing terms by broader, narrower, or related concepts.
The Thesaurus search page provides searching in five databases for controlled terms: Compendex, Inspec, GeoRef, GEOBASE, and PaperChem. Indexers choose terms from this controlled vocabulary to describe the article they index. The controlled vocabulary is used to standardize the way the articles are indexed. Each of these databases is indexed with its own thesaurus.
The Thesaurus function enables you to accomplish the following tasks:
- Improve your search strategy with suggested broader and narrower terms
- Find synonyms and related terms
- Identify controlled vocabulary terms
Thesaurus search returns all terms that match the user's query. The search results are sorted alphabetically: term matches display first, followed by directly related term matches.
How
Follow these steps to perform a Thesaurus search:
- Click ‘Search’ at the top of the page and scroll down to ‘Thesaurus.’
- Click ‘Thesaurus.’ The Thesaurus search page opens.
Select the database you would like to search.
Note: Refer to the individual hyperlinks for each of the six databases listed in this topic's introduction.
- From the Thesaurus search dropdown, select the type of search you want to use. See this FAQ's ‘Selecting a search type in a Thesaurus search’ section for more information.
Enter your search terms in the search text box.
Notes:
- Some terms are common to multiple databases, but many controlled terms are unique to a particular database.
- The Engineering Village interface is not case sensitive, as text can be entered in upper or lower case.
- Click the magnifying glass icon. Your search results appear in a new search results box.
- Use the paging features (left and right arrows) above the new search results box, where applicable, to see additional search results.
Select the checkbox of one or more terms. The terms appear in the ‘Selected term(s)’ box on the right side of the page.
- If desired, click a term to view its thesaurus entry, yielding additional related, broader, and narrower terms.
- Select the checkbox(es) of any of these terms to add to the ‘Selected term(s)’ box.
Notes:
- Terms in italics are lead-in terms that point to a controlled vocabulary.
- Terms followed by an asterisk (*) are former vocabulary terms that point to the current vocabulary terms.
- Returned terms that match the user's search query terms are sorted alphabetically.
- The hierarchical display of your search terms appears above the search box, and you can click any portion of this display to search these narrower, broader, and related search terms.
- If you switch to another thesaurus database after adding terms to the Selected term(s) search box, a message informs you that your selected thesaurus terms will be lost.
- Click ‘OK’ to continue with the database change or
- Click ‘Cancel’ to stop the action.
- Specify how you want Engineering Village to search your selected terms:
- If you select the Boolean operator "AND," all search terms in the Selected term(s) box must be in your results.
- If you select the Boolean operator "OR," your search results may contain any of the terms displayed in the Selected term(s) search box, but not necessarily all of them.
- To limit or specify a sort order of your search results, continue to the section of the Thesaurus search page beneath the Selected term(s) search box. Otherwise, click the magnifying glass icon to run your search.
Delete terms from the Search box or Selected term(s) box
- To delete a term, clear the checkbox preceding the search term from the Search box on the left side of the page or click the ‘X’ following the search term from the Selected term(s) search box on the right side of the page.
- To remove all terms simultaneously, click ‘Reset form.’
GEOBASE Thesaurus searches
The GEOBASE database contains multiple types of controlled terms:- General controlled terms are stored in the Controlled terms field, which is searchable using the CV search code.
- Regional controlled terms are stored in the Geographic terms field, which is searchable using the RGI search code.
Because the GEOBASE thesaurus contains general controlled terms and regional controlled terms, thesaurus queries for this database search both of these fields. This search structure slightly differs from the structure for Compendex, Inspec, GeoRef, and PaperChem queries, in which each query only searches the Controlled term (CV) field.
Refer to Expert search fields and field codes for more information about all search codes.
Click the ‘Scope note’ icon (which resembles a notebook) for controlled terms in Thesaurus search to read Scope notes associated with the search term.
Scope notes are available in thesaurus records for all controlled terms. The Scope notes may include the dates the term was in use (or introduced), plus associated Classification Codes. Scope notes may also include usage notes.
For GeoRef, Scope notes often include maps allowing term visualization.
Compendex vocabulary terms followed by asterisks are former descriptors pointing to the new controlled vocabulary terms for a specific item.
- Enter a search term from the Thesaurus search dropdown.
- Click ‘Search index.’
- Click the checkbox preceding the former vocabulary term (e.g., "Flow of fluids--Visualization*"). This search term displayed in the ‘Selected term(s)’ box.
- Alternately, click the former vocabulary term (e.g., "Flow of fluids--Visualization*"). The new term is displayed in the search box.
- Select the checkbox following the ‘Use:’ label to add the current vocabulary term (e.g., "Flow visualization") to the ‘Selected term(s)’ box.
- If desired, click the new term to see the former terms linked to this new term as well as broader terms, narrower terms, and related terms as available.
In the Thesaurus search, there are three different methods to identify controlled vocabulary terms:
- Vocabulary search
- Exact term
- Browse
Vocabulary search
Select this option if you want to look for a term from a controlled vocabulary along with broader, narrower, or related controlled vocabulary terms. These terms can be searched as full terms or fragments of longer terms. The terms appear in alphabetical order.
- From the dropdown, select ‘Vocabulary search.’
- Enter your search term(s).
- Click the magnifying glass icon beside the search box. The search box with the matching term(s) opens below the Thesaurus search query bar.
- If you enter a search term not in the controlled vocabulary list, the system lists alternate suggestions.
- If any of the suggestions match what you are looking for, select the checkbox for that suggestion, and it will be output in the Selected term(s) search box.
- Click the magnifying glass icon beneath the Selected terms(s) box to run your search.
Exact term
Select this option if you know the exact subject heading and want to see its broader, narrower, or related terms directly.
- From the dropdown, select ‘Exact term.’
- Enter your exact term in the Search box.
Click the magnifying glass icon beside the search box. The main record for the term opens.
This main record may also show broader, narrower, or related terms to illustrate the heading's context in the controlled vocabulary.
For example, the main record for mine ventilation in the Compendex database shows the broader term ventilation and the related terms Mines and mining.
Some narrower terms and related terms can also have narrower terms of their own. If you wish to complete a comprehensive search on a subject, it is beneficial to explore all likely paths for each term.
Example:
A comprehensive search for diodes should include all of the narrower terms, each of which should be explored.
The following narrower terms from Semiconductor diodes cannot be directly searched from the diodes record.
The term "Semiconductor diodes" has the following narrower terms:
- Avalanche diodes
- Gunn diodes
- Light emitting diodes
- Photodiodes
- Power semiconductor diodes
- Tunnel diodes
- Varactors
- Zener diodes
- To find and select these narrower terms, (for this example) select Semiconductor diodes. The narrower terms should also be selected for a comprehensive search.
- If you run an ‘Exact term’ search for a term that is not a controlled vocabulary term, the thesaurus suggests alternate terms.
- Select any of the suggestions so that they will be output into the Selected term(s) search box.
- Click the magnifying glass icon to run your search.
Browse
The Browse option functions in the same manner as an index in a printed thesaurus.
- Select ‘Browse’ to go to the section of the Thesaurus where the term would appear alphabetically.
- Use ‘Previous’ or ‘Next’ to scroll through the entire thesaurus alphabetically.
- Click the magnifying glass icon to run your search.
When submitting a Thesaurus search, you can specify the sort order of results by either relevance or publication year.
- From the Thesaurus search page, select the thesaurus database.
- From the dropdown, select the thesaurus search type.
- Enter search term(s) into the search box.
- Click the magnifying glass icon beside the search box.
- The ‘Sort by’ feature displays below the ‘Selected term(s)’ box results.
- From the ‘Sort by’ feature, select one of the following radio buttons:
- Date (Newest)
- Relevance
- Click the magnifying glass icon below the ‘Selected term(s)’ box to run the search.
The results of the Thesaurus search will be displayed in selected sort order on the Thesaurus results page.
Date (Newest)
Records are primarily sorted by publication year in descending order. The most recent years in your search range are displayed first: 2026, 2025, 2024, 2023, 2022, etc.
An internal weekly load number further sorts these records.
Relevance
The relevance sort is based on an algorithm that takes into account the following criteria:
- Whether the words are found as an exact phrase or separately
- When words are found separately, closer proximity ranks higher
- The number of times that the word or phrase appears in the record
- The word's location within the record
- Words found at the beginning of the field rank higher than words found towards the end
- Whether the words are found within fields designated as particularly relevant, such as the TITLE field
- How often the word appears in the database as a whole
- Words used often are less relevant than words that are less common
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