Perhaps you should try some spelling variations:
sampling using » sampling during, sampling testing, sampling units
ghg sampling » log sampling, light sampling, grab sampling
twinn ian » wing ian
dong sign » among sign, dong bin
ian yang » dan yang, tan yang, wang yang
yang ai » yang di, yang xi, yang yi

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 ian yang ai ghg sampling using ((((dong sin) OR (dong di))) OR (dong sign)) ;~.
• Adding a wildcard symbol may retrieve word variants: twinn ian yang ai ghg sampling using ((((dong sin) or (dong di))) or (dong sign)) ;*.