« AND » allows to search pages which contain all searched keywords (example: meat AND quality)
« OR » allows to search pages containing at least one of the keywords (example: Duroc OR Hampshire)
« NOT » allows to search for pages containing one or many keywords and not one or many others (example: quality NOT fat)
To search an expression or an exact phrase, type it between quotation marks (example: "meat quality")
To combine the AND, OR and NOT operators, you can use parentheses (example: quality AND (meat OR fat))