Perhaps you should try some spelling variations:
decreases sperm » decreased sperm (Expand search), decreases serum (Expand search), decreasing sperm (Expand search)
its professors » with professors (Expand search), in professors (Expand search), to professors (Expand search)
sperm decrease » term decrease (Expand search), speed decrease (Expand search), speed decreases (Expand search)
decrease the » decreases the (Expand search), decrease in (Expand search), decrease of (Expand search)
the decrease » to decrease (Expand search), and decrease (Expand search)
decrease its » decreases its (Expand search), decrease with (Expand search), decrease in (Expand search)
decrease il » decreased il (Expand search), decrease in (Expand search), decrease hiv (Expand search)
il decrease » l decrease (Expand search), will decrease (Expand search), oil 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: "(( decrease the decrease its professors ) OR ( decreases sperm decrease il decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease the decrease its professors ) OR ( decreases sperm decrease il decrease ))*.