Perhaps you should try some spelling variations:
among letters » among lecturers, among learners, among masters
les patients » older patients, aids patients, aims patients
des patients » des patents, des patienten, older patients
wang liang » wang yang
per among » power among, era among, erm among
yang can » yang dean, yang yang, yang jin
yang fan » zhang fan, yang dean, yang yang

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 ((yang can) or (yang fan)) ((les patients) OR (des patients)) per among letters ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang liang ((yang can) OR (yang fan)) ((les patients) OR (des patients)) per among letters ;*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wang liang ((yang can) or (yang fan)) ((les patients) OR (des patients)) per among letters ;*".