Some search engines use symbols or all caps instead of words for their Boolean operations, but nearly all search engines are different:

AND = In Google and Yahoo a space between two words assumes AND.

If you use AND in Yahoo, it must be capitalized.

In other search engines, the + (plus sign) immediately before the second word: universities +norfolk will serve as the AND

Note: In Google, the + immediately before a word means you want that exact word -- without the +, Google automatically searches synonyms.

OR = Google and Yahoo require all caps when using OR.

In Google, the |(pipe sign) also indicates OR.

NOT = In Yahoo, NOT must be capitalized

- (minus sign) is a symbol many search engines use. In Google, the - must be placed immediately before the word/s you want to exclude: automobiles -trucks -vans

 

TIP: It's always good to check HELP screens -- whether you're using a database or a search engine.