Perhaps you should try some spelling variations:
significantly weaker » significantly greater (Expand Search), significantly better (Expand Search), significantly related (Expand Search)
weaker decrease » greater decrease (Expand Search), water decreases (Expand Search)
level decrease » levels decreased (Expand Search), level increased (Expand Search), level disease (Expand Search)
teer decrease » mean decrease (Expand Search), greater decrease (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 ((level decrease) OR (teer decrease))\\") OR (\\"significantly weaker decrease\\"))\"".
• Removing quotes may allow a broader search: (( significant ((level decrease) OR (teer decrease)) ) OR ( significantly weaker decrease )).