I am not a 100% sure i know what you want, but a possible solution would be do your search for the Text you want to exclude and select the values. Then within the triple dots at the top select Alternative or select excluded.
Thanks Mark for your reply, and it is very close to what I want.
Ideally, I would like to exclude any records below containing certain string. For instance, in the below screen, I could get all records containing "NT". But how could I search any records NOT containing "NT?