Keywords are inclusive, so the more keywords you put in, the less lines you'll find.
You can specifically ask for a keyword to not exist by prefixing it with !.
For example, searching for "mouse !cheese milk" would find lines that contain both mouse and milk but not cheese.

[050511 01:17] 3b2aa, ShalladaN: *stretches as he clears the cobwebs*

[050511 01:23] 3b2aa, ShalladaN: *frowns*......well this blows chunks.....

[050511 01:36] 3214a, Peanut: holy crap shalladan

[050511 05:19] edb0f, Peanut: is shalladan aladdin's brother?

[050511 05:19] edb0f, Peanut: because it sure sounds like it!

[050511 05:26] edb0f, Peanut: *pins a "I am in the closet" sign on Matt's back in case of any future visits and poofs*

[050511 06:18] 355e6, Peanut: *tags the room for shits and giggles. More shits than giggles, it would seem...*

[050512 19:28] edb0f, Peanut: three lurkers? whoa

[050512 19:29] edb0f, Peanut: c'mon, bitches! reveal yourselves for the sake of humanity

[050512 19:33] edb0f, Peanut: chicken shits!