Perhaps you should try some spelling variations:
zhang yan » zhang fan, zhang jian, wang yan
hua gene » human gene, a gene, hua ren
wong sau » wong siu, wong shiu, wong lai
wong sam » wong lai, kong sar, von sam
yan yan » yan yuan, nan yan, yang yang
yan hua » tan hua, ya hua, wang hua
yang xi » yang di, yang yi, yang jui

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: zhang yan yan hua gene ((yang judy) OR (yang xi)) ((wong sau) OR (wong sam)) ;~.
• Adding a wildcard symbol may retrieve word variants: zhang yan yan hua gene ((yang judy) or (yang xi)) ((wong sau) or (wong sam)) ;*.