Perhaps you should try some spelling variations:
bhutan gender » rhoton gender
human gender » human gene, german gender, human genome
yan than » van thanh, yan zhang, yan clan
yang jie » yang jin, yang di, yang xi
yang jui » yang judy, yang di, yang xi
wong sau » wong sam, wong siu, wong shiu
wang » wan, lang

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: (wang OR wing) yan than ((human gender) OR (bhutan gender)) ((yang jie) OR (yang jui)) wong sau ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(wang or wing) yan than ((human gender) OR (bhutan gender)) ((yang jie) or (yang jui)) wong sau ;~".
• Adding a wildcard symbol may retrieve word variants: (wang or wing) yan than ((human gender) OR (bhutan gender)) ((yang jie) or (yang jui)) wong sau ;*.