At the moment you probably can't, but you can work around this by using the marking system with a normal search to see which ones you should ignore, or mark only the ones you want by inverting the marking.
Search for the ones you want to ignore, mark them all, then refresh. You will see the items you want in normal, the ones you should ignore in bold. Or you can select them all again, mark them (this will switch marked items to unmarked and vice-versa), so you can use the function select all marked. It's not as good as real filtering but it's better than nothing...