Literature Searching

Top Five Tips From Helen Smith, Agricultural Sciences Librarian

(For full presentation slides see footnote.)

1. Choose the right database

  • No sense searching for genetics information in an art database!
  • Use the PSU Libraries Subject Guides
  • Get in touch with the librarian on the guide for a research consultation

2. Choose the right keywords

  • Retrieving the best articles relies on using the right terms
  • Identify the main concepts of your topic
  • Brainstorm synonyms and alternative phrasings for each concept
  • Use the database’s thesaurus to find more relevant terms
  • Example: What factors affect youth engagement in their personal health?
    • Youth: adolescents, children, teens
    • Health: nutrition
    • Engagement: participation
  • Use Topic Research Worksheet to brainstorm keywords and concepts (p.23)
Topic - youth, has three keywords stemming: adolescents, children, teens. Topic - health, has one keyword: nutrition. topic - engagement, has one key word: participation.
An example of brainstorming topics plus keywords

3. Combining keywords and concepts

  • Librarians call this “Boolean searching”
  • “OR” broadens your search [synonyms or similar concepts]
    • Example: youth OR adolescents
  • “AND” narrows your search [two distinct concepts]
    • Example: youth AND health
  • Combine terms properly
    • Example: youth OR adolescents
Youth and adolescents as a vin diagram.
Using “OR” yields more results
  • Example youth AND health
Youth and Health as a vin diagram
Using “AND” yields fewer, but more precise results

4. Learn to use advanced search features


  • Retrieve items with various word endings and spellings
  • Example: child* will find child, children, or childish
  • Usually the symbol is an asterisk (*), but sometimes it is a question mark (?) or a dollar sign ($)

Phrase Searching

  • For most databases, use quotation marks around a phrase to force the words to be in that order
  • Example: “invasive species” instead of invasive species


  • Many databases have advanced limiting features relevant to the subject
  • Check for limiting by year, publication type, gender, or age groups

5. Follow the citations

Find more studies by using citation searching

Backward searching

  • Look through the reference lists of articles you have found—these references are likely to be relevant for you as well

Forwards searching

  • Find articles that cite older articles. This allows you to move forward from a seminal work and discover what new research is based on that earlier research.
  • Suggested databases: Web of Science and Google Scholar

One more tip: Evaluate and modify your search as necessary

  • Are there other relevant keywords that are showing up in your results? Go back and use those words in your search!

Too Much Information? Try these strategies

  • Add another concept
  • Use only official subject headings (not keywords)—results will be more relevant
  • Search by a notable author
  • Use limits: dates, gender, language, publication type, etc.

Too Little Information? Try these strategies

  • Remove a concept
  • Use more general terms and don’t limit to specific fields
  • Try another database
  • Don’t use limits

It’s an iterative (and some would say never-ending) process.[1]

cycle of three elements: Determine new keywords/terminology/limits, (re)enter search, Evaluate resources found.
The iterative research cycle


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PSU Extension Research Resources Handbook by Creative Commons Licensing is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.