Perhaps you should try some spelling variations:
ratings risk » patients risk
among breast » facing breast, among forest
among east » among ers, among health
lang yan » wang yan, wang yang, zhang yan
yan yang » yang yang, yao yang, dan yang
can past » can east, can fast, can post
can cost » can costa, can lost, can post

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: lang yan yang ((can past) OR (can cost)) ratings risk ((among east) OR (among breast)) ;~.
• Adding a wildcard symbol may retrieve word variants: lang yan yang ((can past) or (can cost)) ratings risk ((among east) or (among breast)) ;*.