Perhaps you should try some spelling variations:
singal processing » singnal processing (Expand search), signal processing (Expand search), sandal processing (Expand search)
during depressed » during depressive (Expand search), during repressive (Expand search), feeling depressed (Expand search)
decrease singal » decrease fungal (Expand search), decrease renal (Expand search), decrease striatal (Expand search)
decrease during » increase during (Expand search), increases during (Expand search), increased during (Expand search)
depressed on » depressed and (Expand search), expressed on (Expand search), depressed nk (Expand search)
on decrease » on decreased (Expand search), of decrease (Expand search), or decrease (Expand search)

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease _ decrease singal processing ) OR ( decrease during depressed on decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease _ decrease singal processing ) OR ( decrease during depressed on decrease ))*.