Perhaps you should try some spelling variations:
trend yang » trend change
oil trend » oil rent, social trend
yan clan » das clan, yan guan, yan yuan
clan oil » can oil, plant oil, coal oil
hong hai » shang hai, zhong tai, dang hai
yang yi » yang di, yang xi, yang jui
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 clan oil trend yang yi ((hong hai) or (hong yu)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang yan clan oil trend yang yi ((hong hai) OR (hong yu)) ;.
• Adding a wildcard symbol may retrieve word variants: wang yan clan oil trend yang yi ((hong hai) or (hong yu)) ;*.