Boolean Operators
Boolean operators are connecting words in keyword searches to narrow or broaden a search. There are three Boolean operators: AND, OR, and NOT.
Use AND to narrow a search and look for two or more terms in your result. AND combines terms and returns the least number of results. Example: The search "chronic pain" AND "women" will provide results that include both the terms "chronic pain" and "women" in the text.
Use OR to broaden a search and find one or both terms in the results. Using OR will return a greater number of results. Example: The search "cardiovascular" OR "heart disease" will return results that include the word "cardiovascular," the phrase "heart disease," or both "cardiovascular" and "heart disease" in the text.
Use NOT to narrow a search by excluding a term from a search. NOT is the least commonly used Boolean operator, but it is useful to narrow down a search. Example: The search "mental health" NOT "depression" will give results that include the phrase "mental health" but not the word "depression."
Image from Research 101 LibGuide from Mississippi College
Search Strategies
Keyword Searching
A keyword is a word or phrase that describes a topic or subject. A keyword search looks for words or terms in any part of the text. Keyword searching is also known as "free-text searching" and is typically how you search when you search on the web. When using keyword searching, you can search for a single word (ex. "cardiology") or a phrase (ex. "heart disease"). When searching for phrases, be sure to include the exact phrase in quotation marks. You can also search for multiple keywords using Boolean operators (AND, OR, NOT).
Controlled Vocabulary
A controlled vocabulary is a list of standardized subject terms or subject headings used to describe what a source is about. Using a controlled vocabulary to search allows you to easily identify more sources on similar topics. Databases typically have a controlled vocabulary in the form of a Subject Headings list or Thesaurus.
Truncation/Wild Card Characters
Truncation is a way to broaden your search to include various word endings and spellings. When using truncation to search, enter the root of a word and put a truncation symbol (*) at the end. Example: child* = child, childs, children, childrens, childhood
Wild Card Characters are similar to truncation and are used to substitute a symbol for one letter of a word. Wild Card Characters are useful if a word is spelled in different ways but has the same meaning. For example, "woman" and "women" have the same general meaning, so you could search "wom!n" to search for both terms. Common Wild Card symbols include !, ?, and #. Symbols may vary by database.
