What is Boolean Search?
The Boolean method of searching began with George Boole (1815–1864), a mathematician who created the method for symbolic logic. Now, his method is used for most database inquiries.
Boolean techniques include using the words AND, OR, and NOT (known as Boolean operators) in combination with other techniques to limit, expand and define your search.
Use AND to narrow your search: all of your search terms will appear in the results.
Example: Medication error AND hospitals
Use OR to broaden your search by connecting two or more synonyms.
Example: online courses OR Web-based instruction OR distance education
The database retrieves all the records containing one term, the other, or both.
Use NOT to exclude term(s) from your search results.
Example: infection control NOT nursing homes
This technique can also be used with the Boolean search terms and will help to expand a search. Depending on the search engine or database, the symbol used may be *, ?, or #. By using the symbol, the database will pull up the word with all possible endings.
Child* will pull up children, childhood, childish
For further tips check the following links.

Still not sure? Ask a Learning Skills teacher or a librarian.

"Bearded Boolean" by - luz - is licensed under CC BY-NC-SA 2.0