Perhaps you should try some spelling variations:
by preprocessing » the preprocessing (Expand search), and preprocessing (Expand search), via preprocessing (Expand search)
decrease ratio » decreased ratio (Expand search), decrease at (Expand search), decreased rate (Expand search)
ratio decrease » to decrease (Expand search), rats decreases (Expand search)
python python » pythons python (Expand search), piton python (Expand search), pitons python (Expand search)
decrease by » decreased by (Expand search), decrease in (Expand search), decrease of (Expand search)
python code » python coding (Expand search), python redes (Expand search)
code python » codigo python (Expand search), pacote python (Expand search)

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

• Removing quotes may allow a broader search: (( decrease ratio decrease by preprocessing ) OR ( python code python python programming ))~.