Perhaps you should try some spelling variations:
teaching object » teaching subject (Expand search), teaching project (Expand search), learning object (Expand search)
decrease their » decrease the (Expand search), increase their (Expand search), decreases the (Expand search)
their decrease » the decrease (Expand search), their disease (Expand search), the decreased (Expand search)
decrease rate » decreased rate (Expand search), decreases rate (Expand search), decrease at (Expand search)
rate decrease » rats decreases (Expand search), rate increase (Expand search), to decrease (Expand search)
decrease risk » decreased risk (Expand search), increase risk (Expand search), decrease in (Expand search)
case teaching » care teaching (Expand search), face teaching (Expand search), game teaching (Expand search)
risk case » risk caused (Expand search), risk based (Expand search), risk phase (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 their decrease rate decrease ) OR ( decrease risk case teaching object ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease their decrease rate decrease ) OR ( decrease risk case teaching object ))*.