Perhaps you should try some spelling variations:
optimum training » optimum planting (Expand search), optimum spacing (Expand search)
reverse optimum » reverse optimal (Expand search)
decrease and » decreases and (Expand search), decrease in (Expand search), decrease the (Expand search)
and decrease » and decreases (Expand search), and decreased (Expand search), and increase (Expand search)
decrease at » decrease akt (Expand search), decrease in (Expand search), decrease _ (Expand search)
decrease of » decrease in (Expand search)
of decrease » or decrease (Expand search), not decrease (Expand search), to decrease (Expand search)
at reverse » aot reverse (Expand search), and reverse (Expand search), not reverse (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 at reverse optimum training ) OR ( decrease AND decrease of decrease ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease at reverse optimum training ) OR ( decrease and decrease of decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease at reverse optimum training ) OR ( decrease and decrease of decrease ))*.