Still, the same holds for Google as well - sometimes you need to avoid relevant keywords because of the junk they'll bring in, other times you need to add seemingly tangential keywords, and yet other times you need to resort to google's syntax -- quotation marks, +/- and site: prefixes. (alack, poor +, we hardly knew ye)
Stumbling upon the right combination can take quite a bit of work until you've built up experience with both the search engine and the subject material's keywords.
Still, the same holds for Google as well - sometimes you need to avoid relevant keywords because of the junk they'll bring in, other times you need to add seemingly tangential keywords, and yet other times you need to resort to google's syntax -- quotation marks, +/- and site: prefixes. (alack, poor +, we hardly knew ye)
Stumbling upon the right combination can take quite a bit of work until you've built up experience with both the search engine and the subject material's keywords.