Perhaps you should try some spelling variations:
defense learning » defense planning (Expand search), deleuze learning (Expand search), defense training (Expand search)
learning object » learning objects (Expand search)
decrease ratio » decreased ratio (Expand search), decrease at (Expand search), decreased rate (Expand search)
ratio decrease » rate decrease (Expand search), rapid decrease (Expand search), ratio increase (Expand search)
decrease toc » decrease of (Expand search), decrease the (Expand search), decreased to (Expand search)
toc decrease » to decrease (Expand search), the decrease (Expand search), not 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 toc decrease ratio decrease ) OR ( decrease AND defense learning object ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease toc decrease ratio decrease ) OR ( decrease AND defense learning object ))*.