Use Boolean logic to narrow, broaden, or refine the search results.

• AND
  • Intersection
  • Search for two terms or phrases in the same document
  • Example:  stormwater AND bioswale

• OR
  • Inclusion
  • Search for either term or phrase separately as well as together
  • Example:  phosphorous-phosphate OR nitrogen-nitrate

• NOT
  • Exclusion
  • Remove the search term or phrase from the results
  • Example:  math union NOT labor

Video:  https://www.youtube.com/watch?v=bCAULDuMcso

• Phrase searching (using quotations around phrases or titles)
  • Examples: 
    • "stormwater quality conditions"
    • "drinking water"
    • "E. coli"
    • "Water Filtration Practices : Including Slow Sand Filters And Precoat Filtration"
• Truncation:  Search for variations in a word by using an asterisk
  • Examples:
    • filt*
      • filter
      • filtration
      • filters
      • filtering
      • filters
    • child*
      • child
      • children
• Parenthesis:  Grouping key search terms/phrases
  • Examples:
    • drinking water AND (law OR policy OR regulation)
    • water filt* AND (e. coli OR "escherichia coli")

Video:  https://www.youtube.com/watch?v=Ed7EswsnEbM

In order to find relevant research, you want to know "What am I looking for?"

1. Write a well-defined research question
2. Pick the key themes in the research question
3. Find a controlled vocabulary term e.g. Library of Congress subject heading (LCSH) or medical subject heading (MeSH)
4. Brainstorm other possible keywords
5. You can write different variations of a search string combining the key themes, controlled vocabulary, and/or keywords

The video https://www.screencast.com/t/WpdeZKZNNx gives an example of how to do so.