Boolean operators form the basis of database logic and are used to create true/false statements.

• The three basic Boolean operators are: AND, OR, and NOT.
• They connect your search words together to either narrow or broaden your set of results in order to find exactly what you're looking for.
• Example: 
  • Tuscarora (title) AND Wallace (author)

See bottom columns for more information on how to conduct searching, or see the reference librarian for an appointment.

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. For example, the phone book's Yellow Pages use subject headings. If you look for "Movie Theatres" you will find nothing, as they are listed under the subject heading "Theatres - Movies."

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:

Use AND in a search to:

• narrow your results 
• tell the database that ALL search terms must be present in the resulting records 
• example: cloning AND humans AND ethics

Be aware:  In many, but not all, databases, the AND is implied.  

• For example, Google automatically puts an AND in between your search terms. 
• Though all your search terms are included in the results, they may not be connected together in the way you want.
• For example, this search:  college students test anxiety  is translated to:  college AND students AND test AND anxiety. The words may appear individually throughout the resulting records.
• You can search using phrases to make your results more specific.
• For example:  "college students" AND "test anxiety". This way, the phrases show up in the results as you expect them to be.

Use OR in a search to:

• connect two or more similar concepts (synonyms)
• broaden your results, telling the database that ANY of your search terms can be present in the resulting records
• example: cloning OR genetics OR reproduction

Use NOT in a search to:

• exclude words from your search
• narrow your search, telling the database to ignore concepts that may be implied by your search terms
• example:  cloning NOT sheep

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)

Some websites support diacritics (a symbol that tells a reader how to pronounce a letter). 

Databases the do not use diacritics when searching:

• NARA

Databases that can use diacritics when searching: