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Searching the Literature: A Guide for Nurses : Step 4: Search Tips

Search Operators (AND, OR, & NOT)

These operators can be used in Library databases, but also work really well in Google!

Operator Purpose Example Search Visualization

Expands the search.

Used to string synonyms together.

Results include all articles with any of the terms used.

Hand washing


Hand Hygiene

(all results including the words "hand washing" as well as all results including the words "hand hygiene")

venn diagram - union of two sets with search terms 'hand washing' and 'hand hygiene'

Narrows the search.

All retrieved results must include all terms connected with AND.

AND usually combines different concepts together in one search.

Hospital infection



(only results that include both the terms "hospital infection" and "antibiotic")

venn diagram - intersection of two sets with search terms 'hospital infection' and 'antibiotic'

Excludes results with a specific term.

Really handy to eliminate unwanted search results.




(all results with the term "antibiotic", but excluding those with the term "penicillin")

venn diagram - relative compliment of terms 'antibiotic' not 'penicillin'


A wildcard is a character that can be substituted for one or more characters in a search term. These work in most databases & also in Google.

Common wildcards include:

Asterisk—can be used for any number of characters, but is most often used with a root word.

Example: Using the term microb* will search for all possible endings of that word, including microbe, microbial, microbiotic, microbiology, etc.

Question Mark—can be used to represent a character that is missing. It is most often used to retrieve all word variants.

Example: Searching for colo?r will return results with color and colour.

Phrase Searching

Use quotation marks to search for phrases. Phrase searching is excellent when the desired result is specificity.

Example: Searching for "nosocomial infections" will retrieve results where both terms are used together in the specified order.

CAUTION! Do NOT use phrase searching in PubMed! It turns off Automatic Term Mapping. Just don't do it!

Google Site Searching

Google site searching can help search across various government websites or can help you better search poorly indexed websites. Site searches should be typed into the browser search bar (where the web address is located). Some browsers will

Site Searching by URL

  • site:URL plus search terms
Example: influenza will retrieve results from only the CDC's website that are related to influenza.

Site Searching by Domain

Example: influenza will retrieve results from all websites ending in .gov with the term influenza.

Mining Reference Lists

When you find a great article, look at its list of references (bibliography) for more relevant articles. If the article you found is perfect for your research, it is likely that it cited many other articles that will also be important to your research.

When you find an article in a reference list that you would like to locate, just copy the title and paste it into the Library's search box. If you cannot locate the article this way, try pasting it into Google Scholar. (REMEMBER: Only use Google Scholar through the Library's website. Click on "Databases" on the search box to locate Google Scholar.)

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