Content created by MIT Libraries, adapted under the Creative Commons Attribution Non-Commercial License.
Boolean operators form the basis of mathematical sets and database logic.
Why use Boolean operators?
Root words that have multiple endings. Example: sun = suns, sunshine, sunny, sunlight
Words that are spelled differently, but mean the same thing. Example: color, colour
Truncation/wildcard symbols vary by database. Check the help screens to find out which symbols are used.
Truncation:
Truncation, also called stemming, is a technique that broadens your search to include various word endings and spellings.
Wildcards:
Similar to truncation, wildcards substitute a symbol for one letter of a word.
If you have questions about applying this technique to your search, Ask Us!
To find subject headings for your topic:
Another way to find subject headings:
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:
Keywords
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Subjects
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When you search a database and do not get the results you expect, Ask Us for advice.
Records in library databases are comprised of fields containing specific pieces of bibliographic information. Common fields include:
Need help understanding fields? Please Ask a Librarian.
The record belows shows the field names on the left: Author, Title, Source, Standard No., Details, Language, Abstract, Descriptor
Most databases allow you to specify that adjacent words be searched as phrases.
Stop words are frequently occurring, insignificant words that appear in a database record, article or web page.
Common stop words include:
Why should you care about stop words?
How can you avoid using stop words in your search?
Choose the most significant words that describe your topic and connect them together using Boolean operators or proximity operators.
Search for your terms in specific fields, such as author, title or subject/descriptor.