Perhaps you should try some spelling variations:
yala human » data human, malawi human
human gene » human genome, human gender, human bone
dong nana » dong nan, dong yang
nana yala » nana yaa
gene yang » gene bank
zhong tai » hong tan, hong hai, zhong zhi
yang tan » yang fan, yang dean, yang yang

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: dong nana yala human gene yang tan ((dang hai) OR (zhong tai)) ;~.
• Adding a wildcard symbol may retrieve word variants: dong nana yala human gene yang tan ((dang hai) or (zhong tai)) ;*.