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Subject heading vs Keywords

Subject Headings Official terms or controlled vocabulary designated by a body of authority (such as the National Library of Medicine's Medical Subject Headings, or MeSH). These are based on a hierarchy of terminology to help organize vast amounts of information within a discipline (MeSH) or just in general (Dewey or Library of Congress). 
Keywords Words or terms you come up with, whether they are casual, layperson terms (like 'flu' instead of influenza); or clinical or scientific terms. You naturally use keywords in Google, Amazon, etc.

How to Use:

Subject headings are ways to organize and find information on a topic. When you search you may struggle to find the best word to use - subject headings take out the guess work. Think of it as the difference between searching for "stroller" versus "Baby Jogger City Mini GT". In the medical world, subject headings can keep you from juggling all the various ways professionals refer to a problem or intervention. Academic databases give more weight to a subject heading. 

Keywords are very useful for fine-tuning those subject headings. In the stroller scenario, you could add the color or accessory to your search. An example search using a combination of subject headings and keywords:

"Baby Jogger Citi Mini GT" AND yellow

In searching, more does not mean better. Use advanced search options and Boolean operators (AND, OR, NOT) to save time and bring the best results to the top. Use keywords and subject terms, not sentences, and follow some of these tips & tricks below. 

Search tips


Keywords not working?

Find synonyms (eg.

Look at subject headings for relevant articles/abstracts

Search Google or Wikipedia for inspiration


Too many results you can't use?

Use Boolean operator AND - combine ideas and limit results


Suicide AND Adolescents

Suicide AND Adolescents AND Prevention

Not enough results?

Use Boolean operator OR - broadens search


Teenager OR youth OR adolescent

Mick Jagger OR Rolling Stones

theater OR theatre

Getting the wrong results?

Use Boolean operator NOT (or - sign in Google) - removes word from search

Apple NOT fruit (-fruit)

JAVA NOT coffee (-coffee)

Looking for a phrase? 

Add "quotation marks" - searches for words in sequence

“Martin Luther King Jr”

“bilateral rib fracture”

Word have too many variations?

Wildcard * - looks for all endings

Educat* looks for:






Studies in CINAHL

CINAHL Complete

Limit Publication Type: Systematic Review
Limit Publication Type: Meta Analysis
Limit Publication Type: Meta Synthesis
Limit Publication Type: Randomized Controlled Trial
Limit Publication Type: Clincal Trial
CINAHL Subject Heading: Prospective Studies (Use to find Cohort Studies)
CINAHL Subject Heading: Case Control Studies
Search Title and/or Abstract for phrase: Case Series
Limit Publication Type: Case Study
Limit Publication Type: Practice Guidelines

Studies in PubMed


Limit Article Types: Systematic Reviews
Limit Article Types: Meta-Analysis
Limit Article Types: Randomized Controlled Trial
Limit Article Types: Clincal Trial
MeSH Term: Cohort Studies
MeSH Term: Case Control Studies
Search Title for phrase: Case Series
Limit ArticleTypes: Case Reports
Limit Article Types: Guideline

CINAHL clinical queries

Clinical Queries are sets of filters that make it easier to search for systematic reviews and specific types of research studies. A Clinical Query looks fairly simple but behind each query is a set of search strategies strung together to filter search results to scientifically sound and clinically relevant studies. In CINAHL, the Clinical Queries limiter refines search results in five research areas:

  • Therapy
  • Prognosis
  • Review
  • Qualitative
  • Causation (Etiology)

Three strategies are available for each of the five research areas:

  • High Sensitivity is the broadest search to include ALL relevant material, including less relevant material.
  • High Specificity is the most targeted search to include only the MOST relevant results, thereby eliminating less relevant results.
  • Best Balance is an attempt to strike a balance between Sensitivity and Specificity.  

To view the underlying search strategies for each Clinical Query filter, see the EBSCO Support document:

What Are the Search Strategies Used by CINAHL Clinical Queries?

PubMed clinical queries

Iintended for clinicians, PubMed Clinical Queries are sets of filters that streamline the search for three clinical research areas:

  • Clinical Study Categories (Etiology, Diagnosis, Therapy (default), Prognosis, and Clinical prediction guides
  • Systematic Reviews 
  • Medical Genetics

Two scope filters are provided for the Clinical Study Categories:

  • Broad (default): Sensitive search – retrieves more citations including highly relevant but also less relevant 
  • Narrow: Specific search – retrieves most precise, relevant citations but fewer overall

View this PubMed tutorial for a brief but informative demonstration of the Clinical Queries feature.

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