Perhaps you should try some spelling variations:
decrease ratio » decreased ratio (Expand search), decrease at (Expand search), decreased rate (Expand search)
ratio decrease » rate decrease (Expand search), rapid decrease (Expand search), ratio increase (Expand search)
decrease under » decreases under (Expand search), decrease burden (Expand search), disease under (Expand search)
decrease and » decreases and (Expand search), decrease in (Expand search), decrease of (Expand search)
and decrease » and decreases (Expand search), and decreased (Expand search), and increase (Expand search)
under effect » founder effect (Expand search), order effects (Expand search), border effect (Expand search)
decrease to » decreased to (Expand search), decrease toc (Expand search), decrease the (Expand search)

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

• Removing quotes may allow a broader search: (( decrease and decrease ratio decrease ) OR ( decrease to decrease under effect ))~.