Don't forget that you can search for ads that contain any of a list of words by separating with a |. For instance, if you want any ad that includes the word "sewing" OR the word "fabric", enter "sewing | fabric" (without the quotes) in your search. the | means OR. If you leave it out, you will get only ads that have both words. So you could enter in the search box - sewing | quilt | fabric | material - rather than searching for each one individually.
Edited to say - you can also search for ads that don't contain a word by putting a - in front of it. For instance, if I look for "sewing machine", I get an ad for a Dodge that says it runs like a sewing machine. I can search for 'sewing machine -dodge' (without the quotes) and I don't get the ad for the Dodge.