Perhaps you should try some spelling variations:
variational problems » emotional problems (Expand search)
method variational » methods variational (Expand search), method variations (Expand search), without variational (Expand search)
decrease processes » disease processes (Expand search), defense processes (Expand search), decay processes (Expand search)
decrease decrease » decrease release (Expand search), disease decreases (Expand search), decrease sucrose (Expand search)
python and » python based (Expand search)
and method » and methods (Expand search), based method (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 _ decrease decrease processes ) OR ( python AND method variational problems ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease _ decrease decrease processes ) OR ( python and method variational problems ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease _ decrease decrease processes ) OR ( python and method variational problems ))*.