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Expert Keyword Searching

Keyword Searching

Keyword searching is the type of searching you typically do in PubMed, CINAHL, MGH OneSearch, and many other databases. At it's most basic, it looks at the words you type into the search box and finds articles that contain those words in their titles and abstracts.

Finding the Right Keywords

Because you are looking for words that appear in titles and abstracts, it follows that you need to know which words authors are using to talk about your topic. This can present some problems when you are at the beginning of a project, because you may not know much about your topic and the way people are talking about it yet. That's why your first few searches are less about finding the perfect articles and more about reading titles and abstracts so that you can find the right keywords.

As you read through the titles and abstracts, start collecting words you think might be good search terms.

Organizing your Keywords

Your topic will most likely be made up of several ideas. You might have some words that describe the population you're investigating. You might have others that describe outcomes you are looking for, and so on.

As you collect words for searching, it can be helpful to group these words by idea to help keep yourself organized. Making lists can also help you brainstorm synonyms and alternative endings as well as help you identify areas you're not so sure about.

For example, if I wanted to find information about whether exercise was effective at decreasing fatigue in women who have breast cancer, I might start a chart like this one.

Combining Keywords

Most databases and search engines use Boolean operators to connect your keywords. The operators not only let you combine the different ideas of your topic but also include the synonyms and word variants.

The two most common operators are AND and OR. AND combines different ideas so that you can find articles that contain both terms. OR combines similar ideas so that you can find articles that contain either/any of the terms.


If we use our example topic about women with breast cancer, we might use the connectors like this:

(fatigue OR energy OR tiredness) AND (exercise OR exercising OR yoga)

NOTICE that I put the terms connected with OR inside parentheses. You'll need to do this if you want your search to be interpreted correctly by the search engine.


Using Quotation Marks

Quotation marks around two or more words tell a database search engine that you only want to find articles where those words appear right next to each other.

This can be quite helpful for phrases such as "physical therapy" or "physician assistant," where there could be tons of articles that use those words separately and have nothing to do with physical therapy or physician assistants.

However, be careful. If you use this too much, you can severely limit the articles you see and very likely miss out on useful ones. 

Using Truncation (or word roots)

Computers can be quite literal when it comes to interpreting our commands. In most library databases, when you search for a word, it will look for exactly that word in the titles and abstracts of articles. That can be quite limiting, however, because when you search for "educate," the computer won't make the leap to include articles that use the words "educates," "educated," "educational."

Truncation is a trick that let's you tell the computer to search for the root of a word with any ending. So in the example at the top of the box, when we chop off the end of the word and add an asterisk, all of the sudden our search has expanded to include

  • truncation
  • truncate
  • truncated
  • truncating

... and so on

Keywords and Subject Headings


When you search with keywords, you are trying to find words that authors have used in their titles and abstracts or somehow otherwise appear in the article's entry in a database. Therefore you need to brainstorm all of the possible ways authors could refer to your concept:

"endurance" OR "physical fitness"

"education" OR "training" OR "school" OR "learning"

Subject Headings

You can also search using subject headings. Subject headings are keywords assigned by the databases to describe the concepts in an article and to try to take some of the guesswork out of the job of coming up with keywords. Try searching with subject headings and see how your results differ from searching with just keywords.

Still unsure about subject headings? Watch this video for another explanation as well as tips on how to find them.