Perhaps you should try some spelling variations:
decrease invariant » decreases ovarian (Expand search), decreased ovarian (Expand search)
invariant objects » invariant sets (Expand search), invariant moments (Expand search), invariant tests (Expand search)
decrease risk » decreased risk (Expand search), increase risk (Expand search), decrease hiv (Expand search)
risk decrease » risk decreases (Expand search), risk increase (Expand search), break decrease (Expand search)
in decrease » in decreased (Expand search), on decrease (Expand search), pain decrease (Expand search)

You may be able to get more results by adjusting your search query.

• Removing quotes may allow a broader search: (( decrease in decrease OR decrease ) OR ( decrease risk decrease invariant objects ))~.