Perhaps you should try some spelling variations:
ping wang » ping pong, hong wang
wang sang » wang yang, wang liang, wang yan
chang you » change you, change your, thing you
chang ann » chang min, chang won, chang yun
wong yue » wang yue
yu chen » yu cheng, yulu chen, jui chen
yi chen » jui chen

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: ping wang sang ((yu chen) OR (yi chen)) ((chang you) OR (chang ann)) ((hong yu) OR (wong yue)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ping wang sang ((yu chen) OR (yi chen)) ((chang you) or (chang ann)) ((hong yu) or (wong yue)) ;~".
• Adding a wildcard symbol may retrieve word variants: ping wang sang ((yu chen) OR (yi chen)) ((chang you) or (chang ann)) ((hong yu) or (wong yue)) ;*.