Perhaps you should try some spelling variations:
douglas mair » douglas mary, douglas a, douglas m
douglas bin » douglas b, douglas john
things zeng » things zhang, things end, things using
wang liang » wang yang
yan guan » gan guan, yan yuan, yang guang
yang xi » yang di, yang yi, 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: wang liang ((yang xi) OR (yan guan)) smart things zeng ((douglas bin) OR (douglas mair)) ;~.
• Adding a wildcard symbol may retrieve word variants: wang liang ((yang xi) or (yan guan)) smart things zeng ((douglas bin) or (douglas mair)) ;*.