Perhaps you should try some spelling variations:
cheng zhang » cheng han, zhen zhang, chen zheng
hua cheng » hua chen, huang cheng, yuan cheng
yan yuan » yan guan, fang yuan, nan yan
tan yong » tan hong, tan kong, tan ying
tan yang » dan yang, tan ying, tao yang
yan yan » nan yan, yang yang, wang yan
wang » wing, wan, lang

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 yan) OR (yan yuan)) hua cheng zhang ((tan yong) OR (tan yang)) term ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wang ((yan yan) or (yan yuan)) hua cheng zhang ((tan yong) OR (tan yang)) term ;~".
• Adding a wildcard symbol may retrieve word variants: wang ((yan yan) or (yan yuan)) hua cheng zhang ((tan yong) OR (tan yang)) term ;*.