Perhaps you should try some spelling variations:
closed chain » cold chain, closer than
ren closed » open closed
yang yang » wang yang, wang yan
nan yang » dan yang, nan yan, tan yang
yang hua » wang hua, yang hui, ying hua
wong sau » wong sam, wong siu, wong shiu
ron paul » von paul, robyn paul, robin paul
hua ren » hua chen

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: nan yang yang hua ren closed chain ((wong sau) or (ron paul)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nan yang yang hua ren closed chain ((wong sau) OR (ron paul)) ;*.