Perhaps you should try some spelling variations:
kyoung yun » young yun, kyoung yang, hyoung gun
yan zhang » yuan chang, bin zhang, han chang
zhang yan » zhang fan, zhang jian, wang yan
hua chen » jui chen, yu chen, a chen
yang yun » yang jun, tang yun, yang yue
yan guan » gan guan, yan yuan, yang guang
yan hua » tan hua, ya hua, wang hua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: yan zhang yan hua chen ((yang yun) or (yan guan)) kyoung yun ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: yan zhang yan hua chen ((yang yun) OR (yan guan)) kyoung yun ;*.