Perhaps you should try some spelling variations:
yan yang » yang yang, yao yang, tan yang
dan yang » daun yang, tan yang, wang yang
oil coal » oil cost, oil oil, oil can
plant li » plant life, plant lice, plant oil
hong hai » shang hai, zhong tai, dang hai
hong yu » wong yue
wang » wing, wan, lang

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

• Performing a fuzzy search may retrieve terms with similar spellings: wang ((yan yang) OR (dan yang)) oil coal plant li ((hong hai) or (hong yu)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang ((yan yang) OR (dan yang)) oil coal plant li ((hong hai) OR (hong yu)) ;.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wang ((yan yang) OR (dan yang)) oil coal plant li ((hong hai) or (hong yu)) ;".
• Adding a wildcard symbol may retrieve word variants: wang ((yan yang) OR (dan yang)) oil coal plant li ((hong hai) or (hong yu)) ;*.