Perhaps you should try some spelling variations:
hua patent » how patent, us patent
dong skin » dong sin, dong bin, dof skin
dong sein » dong sin, dong bin, dong wei
a patent » a patient, _ patent, a parent
min cong » minh cong, min hong, min jeong
dong di » dong sin
a min » a main, a mini, a mine

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 skin) OR (dong di))) OR (dong sein)) ya ((hua patent) OR (a patent)) a min cong shu ;~.
• Adding a wildcard symbol may retrieve word variants: ((((dong skin) or (dong di))) or (dong sein)) ya ((hua patent) or (a patent)) a min cong shu ;*.