Perhaps you should try some spelling variations:
significantly improve » significantly improved (Expand Search)
significantly linear » significant linear (Expand Search), significantly lower (Expand Search), significantly longer (Expand Search)
improve decrease » improve disease (Expand Search), improved urease (Expand Search), improves disease (Expand Search)
linear decrease » linear increase (Expand Search)

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

• Removing quotes may allow a broader search: (( significantly linear decrease ) OR ( significantly improve decrease )).