Perhaps you should try some spelling variations:
heat gain » health gain, health gains, wheat grains
dong yang » dong hoang, wang yang, yang yang
dong nan » dong sin, dong bin, dong cao
hua gain » run gain, hua ban, via gain
long shu » cong shu, tong shui
yan jiu » yang jie, yang jin, pang jiu
long du » long d, long do, long run

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((dong nan) or (dong yang)) ya ((hua gain) or (heat gain)) yan jiu ((long shu) OR (long du)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((dong nan) OR (dong yang)) ya ((hua gain) OR (heat gain)) yan jiu ((long shu) OR (long du)) ;.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((dong nan) or (dong yang)) ya ((hua gain) or (heat gain)) yan jiu ((long shu) OR (long du)) ;".
• Adding a wildcard symbol may retrieve word variants: ((dong nan) or (dong yang)) ya ((hua gain) or (heat gain)) yan jiu ((long shu) OR (long du)) ;*.