Perhaps you should try some spelling variations:
optimal preprocessing » optical processing (Expand search), spectral preprocessing (Expand search), data preprocessing (Expand search)
decrease optimal » decrease intimate (Expand search), discrete optimal (Expand search), decrease stigma (Expand search)
decrease can » decrease in (Expand search), decrease at (Expand search), decrease on (Expand search)
can decrease » can increase (Expand search), to decrease (Expand search), the decrease (Expand search)
decrease and » decreases and (Expand search), decrease in (Expand search), decrease of (Expand search)
and decrease » and decreases (Expand search), and decreased (Expand search), and increase (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 can decrease optimal preprocessing ) OR ( decrease OR decrease AND decrease ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease can decrease optimal preprocessing ) OR ( decrease OR decrease and decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease can decrease optimal preprocessing ) OR ( decrease OR decrease and decrease ))*.