Perhaps you should try some spelling variations:
sampling testing » sampling using, sampling weighting, sampling design
ghg sampling » log sampling, light sampling, grab sampling
twinn dan » twinn ian, finn dan
dong sign » among sign
dan yang » daun yang, tan yang, wang yang
dong bin » dong di, dann bin
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: twinn dan yang yi ghg sampling testing ((((dong bin) OR (dong sin))) OR (dong sign)) ;~.
• Adding a wildcard symbol may retrieve word variants: twinn dan yang yi ghg sampling testing ((((dong bin) or (dong sin))) or (dong sign)) ;*.