Search Terms
Searching for information is always iterative - you try, adjust, and try again. This is especially true for search terms.
Search terms should represent the primary concepts of your question. If you built a good PICO question, you should already have the basic concepts for your search.
Create a list:
- synonyms
- alternate spellings (e.g. British versus American English)
- punctuation (hyphen or no hyphen)
- acronyms and spelled out acronyms
- narrower & broader terms
- plural and singular
Use subject matter words only.
Do not use:
- comparative words (effect, impact, reaction, cause)
- prepositions (during, due to, within, without)
- interrogative words (e.g. how, when, why, what)
These are often called "stopwords". There is a list of all the stopwords in PubMed.
Synonyms & Term Mapping
You can make a grid or a map to help you visualize multiple search terms.
Grid
EXAMPLE PICO Question: In post-menopausal women does hormone replacement therapy compared to no HRT increase the risk of breast cancer?
|
Patient/Problem |
Intervention | Comparison | Outcome |
| post-menopausal women | hormone replacement therapy | no hormone replacement therapy | increased risk of breast cancer |
|
post menopause post-menopause post menopausal post-menopausal postmenopause postmenopausal |
hormone replacement therapy HRT menopausal hormone therapy MHT estrogen replacement therapy estrogen progestin replacement therapy |
breast cancer breast carcinoma breast tumors breast neoplasm mammary cancer |
Map
Maps can be handwritten, making them a fast method for visual thinkers.
Keywords or Subject Headings?
For a quick search, we recommend that you primarily rely on searching by keywords. If that is unsuccessful, you can try searching by subject headings or ask a librarian for help.
More advanced literature searches should use both keywords and subject headings.
Keywords = "natural language"
The terms you would naturally use to speak about and describe concepts. This includes both common language and medical or health sciences terminology you would use with fellow practitioners.
Databases generally locate those keywords in the title, journal name, author name, abstract, and their own specially applied keywords and subject headings in the article records. They generally will NOT search the full text of the article.
Subject Headings = "controlled vocabulary"
A set of standardized words that a database uses to describe concepts (e.g.: "breast neoplasm" to describe breast cancer or breast carcinoma). These preferred, standardized words are mapped to other variant terms for that concept and then applied to every single article in the database that discusses that concept.
To search by subject heading, use the database's thesaurus or medical subject heading (MeSH) search builder. PubMed will attempt to do this for you automatically if you search by keywords. Ask a librarian for help if you are not certain how to do this.