Perhaps you should try some spelling variations:
decrease during » increase during (Expand search), increases during (Expand search), increased during (Expand search)
during decrease » during increased (Expand search), during depressed (Expand search), during disease (Expand search)
decrease mask » decrease risk (Expand search), decrease milk (Expand search), decreased base (Expand search)
decrease not » decrease of (Expand search), decrease akt (Expand search), decrease at (Expand search)
not decrease » to decrease (Expand search), not increase (Expand search), and decrease (Expand search)
mask object » mass objects (Expand search), dark object (Expand search), based object (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 AND decrease during decrease ) OR ( decrease NOT decrease mask object ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease AND decrease during decrease ) OR ( decrease not decrease mask object ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease AND decrease during decrease ) OR ( decrease not decrease mask object ))*.