Perhaps you should try some spelling variations:
human gender » bhutan gender, german gender, human genome
human gene » human genome, human bone, human genetic
wing tan » wing ian, liang tan, hong tan
tan than » tan tan, tran thanh, tan shawn
wong sam » wong sau, wong lai, kong sar
yan jiu » yang jie, yang jin, pang jiu
yang » lang, wang

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: wing tan than ((human gender) OR (human gene)) ((yan jiu) OR (yang di)) wong sam ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wing tan than ((human gender) OR (human gene)) ((yan jiu) or (yang di)) wong sam ;~".
• Adding a wildcard symbol may retrieve word variants: wing tan than ((human gender) OR (human gene)) ((yan jiu) or (yang di)) wong sam ;*.