Perhaps you should try some spelling variations:
patients risk » patient risk, patients links, patients si
among breast » among east, facing breast, among forest
wang yang » wang yan, wang liang, wang yanling
yang yang » wang yan
yang fan » zhang fan, yang dean, yang jin
fan cost » can cost, can costa, iran cost

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

• Performing a fuzzy search may retrieve terms with similar spellings: wang yang yang fan cost ((ratings risk) or (patients risk)) among breast ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang yang yang fan cost ((ratings risk) OR (patients risk)) among breast ;*.