Perhaps you should try some spelling variations:
significant optimization » significant limitation (Expand Search), significant application (Expand Search), significant association (Expand Search)
optimization degree » optimization design (Expand Search), optimization search (Expand Search)
teer decrease » mean decrease (Expand Search), greater decrease (Expand Search)
a decrease » _ decrease (Expand Search), _ decreased (Expand Search), _ decreases (Expand Search)

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( significant ((teer decrease) OR (a decrease)) ) OR ( significant optimization degree ))~".
• Adding a wildcard symbol may retrieve word variants: (( significant ((teer decrease) OR (a decrease)) ) OR ( significant optimization degree ))*.