Perhaps you should try some spelling variations:
operational problems » variational problems (Expand search), emotional problems (Expand search), operational processes (Expand search)
disease operational » disease rational (Expand search), disease international (Expand search), disease computational (Expand search)
decrease akt » decrease at (Expand search), decrease and (Expand search), decrease after (Expand search)
akt decrease » and decrease (Expand search), not decrease (Expand search), any decrease (Expand search)
decrease the » decreases the (Expand search), decrease in (Expand search)
the decrease » to decrease (Expand search), and decrease (Expand search), _ decrease (Expand search)
decrease of » decrease in (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 of disease operational problems ) OR ( decrease akt decrease the decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease of disease operational problems ) OR ( decrease akt decrease the decrease ))*.