Perhaps you should try some spelling variations:
significantly improved » significantly increased (Expand Search)
significantly changed » significantly enhanced (Expand Search), significant changes (Expand Search), significant change (Expand Search)
improved decrease » improved urease (Expand Search), marked decrease (Expand Search)
changed decrease » marked decrease (Expand Search), larger decrease (Expand Search), change increases (Expand Search)

You may be able to get more results by adjusting your search query.

• Removing quotes may allow a broader search: (( significantly changed decrease ) OR ( significantly improved decrease )).