This works:
=MATCH($F1, "searchterm")
and this works:
=SEARCH($F1, "searchterm")
These don't:
=NOT(MATCH($F1, "searchterm"))
=NOT(SEARCH($F1, "searchterm"))

This works:
=MATCH($F1, "searchterm")
and this works:
=SEARCH($F1, "searchterm")
These don't:
=NOT(MATCH($F1, "searchterm"))
=NOT(SEARCH($F1, "searchterm"))