Perhaps you should try some spelling variations:
litter decreased » litter decrease (Expand search), life decreased (Expand search), with decreased (Expand search)
decrease litter » increased litter (Expand search), decrease after (Expand search), decreases liver (Expand search)
fear processing » pear processing (Expand search), fur processing (Expand search), after processing (Expand search)
decrease theory » decrease their (Expand search), decrease the (Expand search), decreased memory (Expand search)
theory decrease » the decrease (Expand search), therapy decreases (Expand search), memory decreases (Expand search)
decreased fear » decreased heart (Expand search), decreased mean (Expand search), decreased after (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 litter decreased fear processing ) OR ( decrease _ decrease theory decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease litter decreased fear processing ) OR ( decrease _ decrease theory decrease ))*.