Perhaps you should try some spelling variations:
significantly mediate » significantly mediated (Expand Search), significantly moderate (Expand Search), significantly predicted (Expand Search)
significantly improve » significantly improved (Expand Search)
mediate decrease » mediated defense (Expand Search), mean decrease (Expand Search)
improve decrease » improve disease (Expand Search), improved urease (Expand Search), improves disease (Expand Search)

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

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