Perhaps you should try some spelling variations:
tuan china » wuhan china, can china, taiwan china
zhang han » zhang fan, zhang hanmo, zhang zhang
zhang yan » zhang fan, zhang jian, wang yan
wing tan » wing ian, liang tan, hong tan
thanh vu » thanh van, thanh _
tan yong » tan hong, tan kong, tan yang
yong jui » yang jui, yang jun, yong cai

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: wing tan ((thanh vu) OR (tuan china)) tan yong jui ((zhang han) OR (zhang yan)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wing tan ((thanh vu) or (tuan china)) tan yong jui ((zhang han) OR (zhang yan)) ;~".
• Adding a wildcard symbol may retrieve word variants: wing tan ((thanh vu) or (tuan china)) tan yong jui ((zhang han) OR (zhang yan)) ;*.