Perhaps you should try some spelling variations:
significantly improved » significantly increased (Expand Search)
significantly alter » significantly altered (Expand Search), significantly smaller (Expand Search), significantly better (Expand Search)
improved decrease » improved urease (Expand Search), marked decrease (Expand Search)
alter decrease » larger decrease (Expand Search), water decreases (Expand Search), teer decrease (Expand Search)

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

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