Perhaps you should try some spelling variations:
real effective » an effective (Expand search), are effective (Expand search)
spp decreased » spp decrease (Expand search), spp increased (Expand search), and decreased (Expand search)
decreased and » decreases and (Expand search), decrease and (Expand search), decreased in (Expand search)
decrease real » decrease renal (Expand search), decreased renal (Expand search), decreases renal (Expand search)
decrease spp » decrease sod (Expand search), decrease std (Expand search), decrease soon (Expand search)
and decrease » and decreases (Expand search), and decreased (Expand search), and increase (Expand search)
in decrease » in decreased (Expand search), on decrease (Expand search), pain decrease (Expand search)

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( decrease spp decreased AND decrease ) OR ( decrease in decrease real effective ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease spp decreased and decrease ) OR ( decrease in decrease real effective ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease spp decreased and decrease ) OR ( decrease in decrease real effective ))*.