Perhaps you should try some spelling variations:
decrease quality » increase quality (Expand search), disease quality (Expand search)
quality problems » quality programs (Expand search), quality program (Expand search), quality protein (Expand search)
decrease signal » increased signal (Expand search), decrease renal (Expand search), decrease stigma (Expand search)
python code » python coding (Expand search), python redes (Expand search)
pitons » citons (Expand search), pitoni (Expand search), pitoes (Expand search)

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

• Removing quotes may allow a broader search: (( decrease signal decrease quality problems ) OR ( python code pitons python programming ))~.