Perhaps you should try some spelling variations:
decreases sperm » decreased sperm (Expand search), decreases serum (Expand search), decreasing sperm (Expand search)
decrease ligand » decrease and (Expand search), decrease lipid (Expand search), decrease lodging (Expand search)
ligand decrease » and decrease (Expand search), ligand release (Expand search), ligands increased (Expand search)
sperm decrease » term decrease (Expand search), speed decrease (Expand search), speed decreases (Expand search)
decrease past » decrease akt (Expand search), decrease at (Expand search), decreases pain (Expand search)
or decreases » or decrease (Expand search), oic decreases (Expand search), oil decreases (Expand search)
decrease or » decrease of (Expand search), decrease on (Expand search), decrease pro (Expand search)
past basic » at basic (Expand search), 1st basic (Expand search), east basin (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 OR decreases sperm decrease ) OR ( decrease ligand decrease past basic ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease or decreases sperm decrease ) OR ( decrease ligand decrease past basic ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease or decreases sperm decrease ) OR ( decrease ligand decrease past basic ))*.