Perhaps you should try some spelling variations:
concrete objects » concrete effects (Expand search), concrete subjected (Expand search), concrete beams (Expand search)
decrease ratio » decreased ratio (Expand search), decrease at (Expand search), decreased rate (Expand search)
ratio decrease » rate decrease (Expand search), brazil decrease (Expand search), to decrease (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)

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

• Removing quotes may allow a broader search: (( decrease ratio decrease OR decrease ) OR ( decrease and decrease concrete objects ))~.