How to improve PubMed and Google search results with boolean operators

Use boolean searches to make dataset and literature reviews easier and more efficient at:

• Google (google.com)
• Google Scholar (scholar.google.com), the scholarly literature and patent search engine 
• NCBI databases (including PubMed.gov and PubMed Central)
• Many other search engines and databases

Example search:

(TP53 OR p53) AND (cancer OR elephants OR "cell division" OR "cell cycle") NOT (mice OR mouse)

This searches for the gene name (TP53) or the protein name (p53), plus at least one word or quoted phrase in the second part. It also excludes searches with the terms "mice" or "mouse".

Boolean word operators:

• AND - use before a term you want to include
• OR - use to give alternatives
• NOT - use to exclude terms you don't want

Use the operators in ALL CAPS. Some websites like Google don't care, but many do. 

Boolean symbols:

• + means AND
• | (vertical bar) means OR
• - (hyphen) means NOT
• " " quotes are used to keep words together, e.g. to search "cell division" and not just "cell" or "division"
• ( ) parentheses are used to mix operators

Example re-written with symbols:

+(TP53|p53) +(cancer|elephants|"cell division"|"cell cycle") -(mice|mouse)

Note that some websites don't support the symbols, only the word operators.

More search limits

Google has a lot more tools to refine your searches. For example, narrowing results by url or filetype:  

apples +filetype:pdf +site:.gov

...this narrows the search pdf files on .gov government websites.

Create automatic search alerts

PubMed: create your search and click "Search", then click "Create alert"

PubMed allows daily, weekly, and monthly email alerts. You can select the email format (text or html) and day of delivery, among other settings.

Go to the PubMed Dashboard (found by clicking the person icon on the top right) then "Saved Searches" to edit the search string and email settings later.

Google Scholar: Settings Menu: Alerts: Create Alert

Google Scholar is much simpler. The same page ("Alerts") is where you can create or delete search alerts. 

These skills will help you become more effective when you do a literature review, also called "lit review" and "lit search".