Perhaps you should try some spelling variations:
thuy chen » hua chen, zhu chen
chen kong » chen rong, chen yong, chen dung
kong john » king john, wong john, longo john
yan xuan » yan guan, yan yuan, wang xuan
wong sam » wong sau, wong lai, von sam
wang » wing, wan, lang
sar » sara, star, saur

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: wang yan xuan thuy chen kong john ((wong sam) OR (kong sar)) ;~.
• Adding a wildcard symbol may retrieve word variants: wang yan xuan thuy chen kong john ((wong sam) or (kong sar)) ;*.