Perhaps you should try some spelling variations:
wang sampling » ring sampling, plant sampling, a sampling
sampling down » sampling non, sampling data, sampling box
down human » non human, von human
yang jie » yang jin, yang di, yang jui
wong sau » wong sam, wong siu, wong shiu
yang yi » yang di, yang xi, 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: wang sampling down human brain ((yang jie) OR (yang yi)) wong sau ;~.
• Adding a wildcard symbol may retrieve word variants: wang sampling down human brain ((yang jie) or (yang yi)) wong sau ;*.