Many search mechanisms eliminate 1-letter, 2-letter and 3-letter words, such as the II in World War II, the I in I Have A Dream, or in your case, the W in George W. Bush. Many times, this can be fixed by using the quotation marks, but there may be times when this will not work. Placing a plus sign (+) in front of the word will make sure it is included in the search.
In some databases, using the minus sign (-) works like the not does. You would place it in front of a word you do not want to search.