Possible to negate a search term in advanced bug search ?

Hi, I have a quick usage question:

Is there a way to negate a search term in launchpad.net especially bug search ?

In my project I can look up all LP bugs that are in reality features by searching for "FEAT", since there is an agreement that features have the term "FEAT" in the bug title:
https://bugs.launchpad.net/ubuntu-z-systems/+bugs?field.searchtext=FEAT&orderby=-importance&search=Search&field.status%3Alist=NEW&field.status%3Alist=CONFIRMED&field.status%3Alist=TRIAGED&field.status%3Alist=INPROGRESS&field.status%3Alist=FIXCOMMITTED&field.status%3Alist=INCOMPLETE_WITH_RESPONSE&field.status%3Alist=INCOMPLETE_WITHOUT_RESPONSE&assignee_option=any&field.assignee=&field.bug_reporter=&field.bug_commenter=&field.subscriber=&field.structural_subscriber=&field.tag=&field.tags_combinator=ANY&field.has_cve.used=&field.omit_dupes.used=&field.omit_dupes=on&field.affects_me.used=&field.has_patch.used=&field.has_branches.used=&field.has_branches=on&field.has_no_branches.used=&field.has_no_branches=on&field.has_blueprints.used=&field.has_blueprints=on&field.has_no_blueprints.used=&field.has_no_blueprints=on

But I would ideally also want to look up the rest, so the ones that are NOT features,
hence my question if there is a way to negate a search term?

Btw. "-FEAT" or "!FEAT" does not seem to work (it lists the features again) - I wasn't able to find any hints or tips and tricks on searching within Launchpad ...