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Mechanical Engineering Research Guide

For both new and experienced library visitors: learn about library services and the resources available to faculty, staff, and students in Mechanical Engineering.

Search techniques

This page explores some basic search techniques to help you obtain better, more focused results. These techniques will work, with minor adjustments, in the vast majority of library databases.

Table of Contents

Boolean searching

Boolean searching lets you tell the computer to do certain things with keywords that you are using in your search. Searching this way works in Quick Search as well as in the various databases where you'll find articles, papers, etc.. If you want more help try out the tutorials linked below.

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.

Example search: robotics AND automation
Search results will only contain items which contain the words "robotics" and "automation"; search results will exclude items only on robotics or only on automation.
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)

Example searchdrilling OR boring
Search results will contain items which contain only "drilling", only "boring", and items which contain both both "drilling" and "boring."
NOT (ignore)

NOT is used to specify keywords to ignore, or remove from search results. 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.

Example searchwind turbine NOT environment
These search results should only cover articles about wind turbines that do not involve the environmental impact of turbines.


Nesting is a search technique to optimize results when searching with more than one Boolean operator. Using multiple Boolean operators can introduce unexpected results–using nesting techniques can help reduce this by causing the computer to perform the operation in parentheses first, followed by other operations.

Example nested search: environment AND (fracking OR hydraulic fracturing)
This search will return results containing "environment AND fracking" as well as results for "environment AND hydraulic fracturing" and results containing all of these keywords. The concepts of "environment" and "fracking"/"hydraulic fracturing" will be present in all results.


Example search without nesting: environment AND fracking OR hydraulic fracturing
This search will return results containing "environment AND fracking" as well as those containing just the term "hydraulic fracturing"– without the environment component. Nesting helps ensure that all results contain all concepts of interest.


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 databases use for truncation.

Example good truncation search: sustainab*
This search will return results for sustainable and sustainability. This is a good use of truncation.


Example bad truncation search: sim*
This search will return results for: simulationsimulatesimple, etc. This is not a good use of truncation.

Phrase searching

To search for an exact 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:
"stainless steel" AND "tensile strength"
"offshore wind farm"
"unmanned aerial vehicle"


Most of us are familiar with keyword searches: you enter 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.
  • Avoid contractions, uppercase letters, and punctuation.
  • Do not search for sentences or parts of sentences (unless it's a phrase).

Field searching

Field searching lets you limit where in an item's record the computer searches for a specific term. This is often a major component of a database or other tool's Advanced Search.

Common fields you will see are: author name, title, source title (e.g., journal name), and subject. However, many search tools provide even more options than just these. Choosing a specific field to search tells the computer to only look in that part of the item's record and ignore everything else.

Here are some examples for when field searching might be useful:

  • You know the name of a book's author, but not its title (or vice versa)
  • The author has a name that is the same as a common English word
  • You want to find all articles (or books) written by a particular author
  • You want to see if the library has access to a specific journal
  • You want to find everything in a database on a specific topic

Some tools also let you control how terms in a field search are applied. For example, the ISU Library's Quick Search lets you choose whether results should simply contain those terms (in any order, and with some variations such as plurals), contain those terms exactly as entered, or start with those terms (for titles).