Perhaps you should try some spelling variations:
among donors » among doctors, among actors
do patients » des patients, dtc patients, _ patients
de patients » des patients, de pacientes, les patients
1.8 among » 1.5 among, 19 among, 1 among
yan yang » yang yang, yao yang, tan yang
dan yang » daun yang, tan yang, wang yang

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: wai ((yan yang) OR (dan yang)) fan ((de patients) OR (do patients)) 1.8 among donors ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wai ((yan yang) or (dan yang)) fan ((de patients) OR (do patients)) 1.8 among donors ;~".
• Adding a wildcard symbol may retrieve word variants: wai ((yan yang) or (dan yang)) fan ((de patients) OR (do patients)) 1.8 among donors ;*.