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Health Information Sources & Searching

A guide to finding, identifying, and critically appraising health information.

Boolean Operators

Simple words (AND, OR, NOT) used to find information in a database.

  • AND – Narrows a search by finding references with all the terms connected with the word AND. Useful for combining different concepts.
  • OR – Broadens a search by finding references with any term connected with the word OR. Useful for combining synonyms.
  • NOT – Limits a search by removing references with the words that follow the word NOT. Useful for excluding content. Warning! Using NOT may remove relevant references from your search, so use with caution.

Truncation

The practice of using a symbol to tell the database the find all forms of that word. The symbol is usually an asterisk but can vary by database.

  • Pollut* retrieves pollution, pollutant, polluting, pollute, pollutes, …

Phrase Searching

The use of quotation marks to find an exact phrase.

  • “childhood immunization” will find results with those exact words in that exact order. Do not use phrase searching in PubMed until you first try your search without quotes.

Field searching

Most databases allow you to search specific areas or fields in their records. Field searching can help you focus your search and refine your search results.

Useful tags in PubMed:

  • Title and abstract searching - [title/abstract] or [tiab] looks for terms in titles and abstracts - stroke[title/abstract] OR adult*[tiab]
  • Text word searching - [text word] or [tw] looks for words in text fields including the title, abstract, and MeSH - stroke[tw] OR adult*[tw]

See a database’s help pages to learn more about field searching.

Nesting

Nesting is a search technique using parentheses to group together related keywords or phrases that are connected by the Boolean operator OR.

For example, if you are searching for studies on diabetes, your nested search statement might look like this:

  • (diabetes OR diabetic OR hyperglycemia)

Nesting is also used to combine multiple concepts by linking these grouped terms with other Boolean operators, such as AND. To search for studies on diabetes and hypertension, you could structure your search as:

  • (diabetes OR diabetic OR hyperglycemia) AND (hypertension OR high blood pressure)

Nesting is also used when grouping together two or more operators in a single search statement.

  • i.e., (alcohol AND (cigarette OR tobacco OR nicotine))

 

By nesting terms, you ensure the database interprets your search logic correctly, leading to more precise and comprehensive results.

Wildcards

Characters used to replace another character in a term. Wildcards help find results with variant spellings; they vary by database. Not applicable to PubMed.

  • wom?n or wom#n retrieves woman or women.
  • colo#r retrieves results that include color or colour.

Proximity Operators

Characters used to tell a database how close a word must be to another word. These characters vary by database - see the database’s help pages for more information. You cannot perform proximity searches in PubMed.

EBSCO databases (CINAHL, PsycINFO, …)

  • Nn – Near operator finds references with terms that are within 'n' words of each other in either direction
    • addiction N5 alcohol – finds references where the word “addiction” is within five words of “alcohol” in any order.
  • Wn - Within operator finds references with terms that are within 'n' words of each other in the order in which they are entered.
    • addiction W5 alcohol – finds references where the word “addiction” is within five words of “alcohol” in that order.

Ovid

  • ADJn - Adjacent operator finds references with terms that are within 'n' words of each other in either direction

Embase

  • NEAR/n – Near operator finds references with terms that are within 'n' words of each other in either direction
  • NEXT/n – Next operator finds references with terms that are within 'n' words of each other in the order in which they are entered.

Scopus

  • W/n – Within operator finds references with terms that are within 'n' words of each other in either direction

Additional Tips

  1. See Similar Articles feature: Most databases usually have a link (often visible once you click on the title of an article) that will take you to a list of related articles. This can be a very useful discovery tool. 
  2. Saving searches: Consider saving your searches (especially those for ongoing research) in each database and maybe even in a Word or Excel document as well.
  3. Citation management: Export citations to a citation manager such as Zotero or EndNote. 

Searching Google? Try the following operators to refine a Google search.

  • site: before a domain or site type such as gov, org, or edu to focuses the results to those websites. 
    • site:gov
  • intitle: before a term finds results with that term in the title.
    • intitle:global health
  • -  in front of a word keeps results with that term out of the search results
    • -business
  • OR added between words finds results with those words
    • heart attack OR cardiac attack
  • " " finds an exact phrase 
    • "global health education"
  • AROUND(n) finds results where the terms are up to n number of words away from each other.
    • global AROUND(3) programs