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Environmental Science and Studies Research Guide

This guide serves all of Iowa State's environmental programs as well as the many courses that share themes of sustainability, resource management, and environmental awareness.

Search better

Computers cannot understand language so it's important to give them simple and logical instructions. There are four basic techniques you can use to improve your search skills: keyword searching, Boolean expressions, phrase searching, and truncation. All of these techniques can be combined together to create precise or broad searches.

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Most of us are familiar with keyword searches: you enter in words and you get back results which contain those words. It's important to choose your keywords carefully otherwise you will get no results or the wrong results. Use these basic tips to improve your keywords:

  • Choose the most basic form of a word to use in a search (i.e. use "pizza" instead of "pizzeria")
  • Avoid contractions, uppercase letters, and punctuation.
  • Do not search in sentences or sentence fragments (unless it's a phrase).

AND (find all)

When you combine keywords with AND you will only get results which contain all of the keywords joined by AND.
Use AND when you need to narrow a search to contain ALL keywords.

Search: cat AND dog
Results: will only contain items which contain the words "cat" and "dog"; search results will exclude items only on cats or only on dogs.

OR (find either)

When you combine terms with OR you will get results which contain any of the terms joined by OR.
Use when you want to broaden a search to search for related terms or variant spellings (example: "climate OR climatic OR climates")

Search: cat OR dog
Results: contain items which contain only "cat", only "dog", and items which contain both "cat" and "dog."

NOT (ignore)

NOT is used to specify keywords to ignore. Some search engines and databases don't support NOT (Google uses "-" instead for example). NOT can be useful when you are searching for a word with multiple meanings or need to exclude certain topics from a search.

Search: unmanned aerial vehicle NOT autonomous
Results: should contain sources about unmanned aerial vehicles that are operated by a pilot and not self-controlled.

Phrase searching

To search for a phrase or multi-word concept place the words or phrase in quotation marks. The quotation marks tell the search to find all of these words together in this order.

Example searches:
"To be or not to be" AND shakespeare
"new york city"
"unmanned aerial vehicle"


Truncation is a way to place "wildcard" characters in your searches. This is useful when trying to include word variations in your searches.You need to be careful where you truncate a word - if you truncate too early you may end up with unexpected results that contain unrelated words with the same spellings. The asterisk(*) is the symbol most indexes use for truncation.

Example good truncation search: bacteri*
Results: will cover both bacteria and bacterium. This is a good use of truncation.


Example bad truncation search: creat*
Results: will cover creaturecreationcreatecreatingcreator, etc. This is not a good use of truncation.

Nested Searches (aka combining techniques)

You can use parentheses to group different sets of instructions into one, precise search command. Just like in mathematics, the computer processes the statements in parentheses first, and then applies the commands outside of the parentheses to the results.

Search: (cat OR cats) AND "house train*"
Results: will contain the phrases "house training" or "house train" and also the word "cat" and "cats."


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Lorrie Pellack
Head, Research & Instruction Services Dept.
150c Parks Library
Ames, IA 50011-2140
Phone: 515-294-5569