Perhaps you should try some spelling variations:
their preprocessing » the preprocessing (Expand search), their processing (Expand search), the reprocessing (Expand search)
increase their » increase the (Expand search), increases the (Expand search), increased the (Expand search)
decrease and » decreases and (Expand search), decrease in (Expand search), decrease the (Expand search)
and increase » and increases (Expand search), and increased (Expand search)
decrease α » decrease _ (Expand search), decrease β (Expand search), decrease in (Expand search)
α decrease » _ decrease (Expand search), to decrease (Expand search), or decrease (Expand search)
decrease of » decrease in (Expand search)
of decrease » or decrease (Expand search), not decrease (Expand search), to 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 AND increase their preprocessing ) OR ( decrease α decrease of decrease ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease and increase their preprocessing ) OR ( decrease α decrease of decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease and increase their preprocessing ) OR ( decrease α decrease of decrease ))*.