Is there a way to exclude values from search results in the ThriftDB API? i.e., say I want to, [filter][domain]=nytimes.com&[filter][username]!=ausername

Is there a way to exclude values from search results in the ThriftDB API? i.e., say I want to, [filter][domain]=nytimes.com&[filter][username]!=ausername ...is there a way to do that? I tried the "exclude" operator after [username] and get an "internal server error" every time.