Perhaps you should try some spelling variations:
yang yang » wang yang, wang yan
gene sang » lee sang, gene bank
sang minh » kang minah, anh minh, song min
hua gene » human gene, a gene, hua ren
cong seo » hong seo, cong shu, cong sun
cong van » congo can, duong van, cong sun
yang xi » yang di, yang yi, yang jui
xi hua » xie hua, li hua

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

• Performing a fuzzy search may retrieve terms with similar spellings: yang yang xi hua gene sang minh ((cong seo) or (cong van)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: yang yang xi hua gene sang minh ((cong seo) OR (cong van)) ;.
• Adding a wildcard symbol may retrieve word variants: yang yang xi hua gene sang minh ((cong seo) or (cong van)) ;*.