Search keyword filtering

There are often false 'hits' on searches that I would like to see eliminated. For example, a search for a particular performer's name will return several other similar performers' titles ... even "Alvin xxx" will return tunes by "Alvin & The Chipmunks". If we could specify something like "alvin !!chipmunks" (alvin NOT chipmunks) that would help considerably. On a similar note, a requirement that "x && y" (x AND y) only return a positive would be very helpful.