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EGR 1000 Engineering, Society, and You

An introduction to library services and resources with a focus on resources for engineering.

Subject Headings & Keywords

Keyword vs. Subject Searching

Keyword and subject searching methods are two widely used ways to effectively find items on your topic. They are usually offered to the researcher among other search options by any index, database, or online library catalog. There are important advantages to both methods; knowing how to use them and how they differ from each other will help you retrieve better, more accurate results.

Subject headings describe the content of each item in a database. Use these headings to find relevant items on the same topic.  Searching by subject headings (a.k.a. descriptors) is the most precise way to search article databases. It is not easy to guess which subject headings are used in a given database. 

Keyword searching is how you typically search web search engines.  Think of important words or phrases and type them in to get results.

Here are some key points about each type of search:

Keywords

Subjects
  • natural language words describing your topic - good to start with
  • pre-defined "controlled vocabulary" words used to describe the content of each item (book, journal article) in a database
  • more flexible to search by - can combine together in many ways
  • less flexible to search by - need to know the exact controlled vocabulary term
  • database looks for keywords anywhere in the record - not necessarily connected together
  • database looks for subjects only in the subject heading or descriptor field, where the most relevant words appear
  • may yield too many or too few results
  • if too many results - also uses subheadings to focus on one aspect of the broader subject
  • may yield many irrelevant results
  • results usually very relevant to the topic

Research Tip

Use both keyword searching AND subject searching to get better results:

  1. Start your search with keyword searching; use your own words that describe your topic best.
  2. After getting results, focus on the most relevant record(s), and among subject headings, presented in them; choose the most suitable ones for your topic. In some databases subject headings can also be called "terms" or "descriptors".
  3. Now is the time to turn to subject headings for your further search.

Modifying Your Search

Search Order

Databases follow commands you type in and return results based on those commands. Be aware of the logical order in which words are connected when using Boolean operators: 

  • Databases usually recognize AND as the primary operator, and will connect concepts with AND together first.
  • If you use a combination of AND and OR operators in a search, enclose the words to be "ORed" together in parentheses.

Examples:

  • ethics AND (cloning OR reproductive techniques)
  • (ethic* OR moral*) AND (bioengineering OR cloning)

Too Many Results

Your topic or research question could potentially be too broad, returning a large number of irrelevant results. Since most topics involve multiple aspects and different contexts, you may need to narrow your topic to find acceptable resources. When narrowing a topic, make sure your new search still reflects the main idea.

Here are some techniques to help narrow your topic.

Technique Description Search Example Less Results
Quotations Add quotations around two or more keywords to create a specific search phrase  social justice "social justice"
Add a Focus Too broad of a topic will retrieve too many results. Add a focus to reduce the number. “oil wells” AND construction “oil wells” AND construction AND Texas
Use Boolean Term NOT  Excluding a keyword or phrase from searching will remove any articles referring to that topic.  ethics AND “alternative medicine”  ethics AND “alternative medicine” NOT acupuncture 
Add Keywords The more keywords you add, the fewer results you will get. “rap music” “rap music” AND gender

 

Too Few Results

If you returned too few results, your topic or research question could be too narrow or specific to find enough information. You may need to broaden your topic to find acceptable resources.

Here are some techniques to help broaden your topic.

Technique Description Search Example More Results
Check Spelling Unlike many search engines, databases will not correct a misspelled word. “intrest rates” AND inflation “interest rates” AND inflation
Reduce Keywords The more keywords you have, the lower number of results you will retrieve. bees AND honey AND pollination AND food AND Florida  bees AND pollination AND food
Try Synonyms Replace keywords with different words that have the same or similar meaning.  females AND “relationship abuse” women AND “relationship abuse”
Try Related Terms Use keywords that are related to your topic, but not exactly the same. universities AND “academic achievement” “higher education” AND “academic achievement” 
Add Boolean Term OR  Add OR between synonyms or related terms to expand results. advertising AND children advertising AND children OR teenagers
Change the Focus Too narrow of a focus will produce fewer results. “Seminole County” AND habitat AND “black bears” Florida AND habitat AND “black bears"
Truncation Add an asterisk(*) to the end of a root word to expand search education educat* (education, educated, educator, etc.)