Perhaps you should try some spelling variations:
yang yang » wang yang, wang yan
brain yan » brain gain, brain a
ya human » a human, das human, 2 human
long shu » cong shu, tong shui
yan jiu » yang jie, yang jin, pang jiu
long du » long d, long do, long run
dong » doing, done, hong

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: ((dong sin) OR (yang yang)) ya human brain yan jiu ((long shu) OR (long du)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((dong sin) or (yang yang)) ya human brain yan jiu ((long shu) OR (long du)) ;~".
• Adding a wildcard symbol may retrieve word variants: ((dong sin) or (yang yang)) ya human brain yan jiu ((long shu) OR (long du)) ;*.