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NURS3170: Principles of Evidence-Based Nursing

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Find Subject Headings and Keywords

PICO Question

P: Community-dwelling senior citizens
I: Gardening
C: Not gardening
O: Quality of life, emotional and/or cognitive outcomes

Database Vocabularies

Many library databases will assign a specific list of terms—CINAHL "Subject Headings," PubMed and MEDLINE "MeSH" (Medical Subject Headings), the PsycInfo "Thesaurus"—to represent an idea, instead of relying solely on the keywords or phrases different authors use in their articles. Examine these to find the best terms, and consider your topic from multiple viewpoints:

Subject headings are updated annually, but the updates may lag real-world developments. mRNA Vaccines was added to MeSH in 2022 and CINAHL does not yet offer a subject heading specifically for this concept.

When you find references to relevant articles, examine their subject indexing in a detailed view

  • CINAHL: both Major Subjects and Minor Subjects
  • PubMed: MeSH terms
  • PsycInfo: Subject and perhaps Classification

to find additional subject terms for your search.

If the database record for the item was added recently, it may lack subject headings, but they will be added at a later date.

Tips:

  • Use database tools to find subject headings and keywords: "suggest" options and scope notes
  • Sometimes you will use a limit or filter instead of subject headings, but you may need to use both:
    frail elderly
    frailty AND aged
    frailty with the filter aged, 65+ years
  • Subject headings are similar across health sciences databases, but not exactly the same
  • Try different perspectives on each component to find subject headings and to identify keywords: burn patients have burns+, and burn nurses, whose specialty is burn nursing, care for them in burn units
  • Try using antonyms: if your topic is about drowsiness, add subject headings and keywords about wakefulness or alertness
  • Look for subject headings and keywords in the full text of Cochrane reviews and other evidence or knowledge syntheses
  • Feeling stumped by subject headings? Search for keywords in article titles, and then check the assigned subject headings

Always Use "Explode"

"Explode" in health sciences databases retrieves references containing

[selected subject term] OR [all the more specific subject headings in its "tree" hierarchy or hierarchies]

If you explode the subject heading Face, you will also retrieve articles specifically about Nose, Eyelashes, etc.

PubMed automatically explodes MeSH terms, but you must specify explodes in most other databases.

Save the "Major" Option for Later

Health sciences database indexing usually identifies which subject headings describe the primary topic of an article. Use this feature to reduce an overwhelming number of results that persist after applying all other search terms, limits, and filters.

Use Subheadings Carefully

Use subheadings to create more precise searches if applying all other search terms, limits, and filters returns overly broad results. Select all appropriate subheadings, using the MeSH Qualifiers List and scope notes for guidance.

Aspirin/administration and dosage
Aspirin/therapeutic use

While you can apply subheadings to exploded subject headings, usually they cannot be exploded themselves.

Tips:

  • Use multiple related subheadings. See the MeSH Qualifiers List for logical groupings, which generally apply to CINAHL subheadings as well
  • Consider applying subheadings to multiple subject headings:
    Aspirin/therapeutic use
    Headache/drug therapy

Searching Keywords

Use keywords as well as subject headings to comprehensively search a topic.

  • Keywords may be terms from a scope note, synonyms or related terms, or truncated word stems
  • Include acronyms and abbreviations: BPPV as well as benign paroxysmal positional vertigo
  • Unless you are required to focus on American research, consider adding British keywords to your search strategy:
    estrogen* OR oestrogen*
    emergency OR casualty

Because citations are added to CINAHL and PubMed before they are fully indexed, a search strategy including keywords will retrieve references most recently added to the databases.

Know the Limits and Filters

Most health sciences databases include limits or filters for publication year and for articles written in English (or other languages). You may need to search the "frame" of the database screen or click a button to view all available limits and filters.

Age

  • CINAHL and PubMed use similar categories for age groups
  • PsycInfo includes more specific breakdowns for some age ranges

Research

  • CINAHL and PubMed  subject headings permit finding research by specific methodologies, while PsycInfo applies fewer and broader subject headings
  • CINAHL also includes a general Research Article limit, which excludes other publication types

Publication type

  • PubMed primarily covers journals, but this will include letters to the editor, editorials, and other items that aren't articles. You can identify these by labels in full records.
  • PsycINFO covers many items that aren't journal articles. Combine Record Type and Methodology limits to focus on research articles