Perhaps you should try some spelling variations:
among patients » among nations
patients risk » patient risk, patients links, patients si
among first » among forest, among firms, saving first
liang dan » liang tan, liang sun, wang dan
can among » cancer among
king dan » king eden, king has, king yax

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

• Performing a fuzzy search may retrieve terms with similar spellings: wang ((liang dan) or (king dan)) can among patients risk among first ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang ((liang dan) OR (king dan)) can among patients risk among first ;*.