Perhaps you should try some spelling variations:
dong yang » dong hoang, wang yang, yang yang
dong cao » dong xiao, dong nan, yong cai
a patent » a patient, _ patent, a parent
patent a » patient a, patents a, patent _
dan cao » dan cao's
eu long » au long
long du » long d, long do, long run
ya a » a a, y a, ye a
a eu » _ eu, a e, i eu

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 (dan cao))) OR (dong yang)) ya a patent a eu long du ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((dong cao) OR (dan cao))) or (dong yang)) ya a patent a eu long du ;~".
• Adding a wildcard symbol may retrieve word variants: ((((dong cao) OR (dan cao))) or (dong yang)) ya a patent a eu long du ;*.