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 the » decreases the (Expand search), decrease in (Expand search), decrease of (Expand search)
the decrease » and decrease (Expand search)
decrease to » decreased to (Expand search), decrease toc (Expand search), decrease pro (Expand search)
decrease at » decrease akt (Expand search), decrease and (Expand search), decrease in (Expand search)
at decrease » rate decrease (Expand search), that decrease (Expand search), and decrease (Expand search)

You may be able to get more results by adjusting your search query.

• Removing quotes may allow a broader search: (( decrease to decrease optimal preprocessing ) OR ( decrease at decrease the decrease ))~.