Perhaps you should try some spelling variations:
yang yang » wang yang, wang yan
a patient » _ patient, aids patient
dong cao » dong xiao, dan cao, dong nan
a patent » _ patent, a parent
bau long » au long, bank long, baby long
long du » long d, long do, long run
a bau » a bad, a bab, a ban

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: ((dong cao) OR (yang yang)) ya ((a patent) OR (a patient)) a bau long du ;~.
• Adding a wildcard symbol may retrieve word variants: ((dong cao) or (yang yang)) ya ((a patent) or (a patient)) a bau long du ;*.