Perhaps you should try some spelling variations:
yang guang » yan guan
yang liang » wang liang, yan liang, peng liang
yang yang » wang yang, wang yan
hua gene » human gene, a gene, hua ren
tang kia » tang li, kang kim, pang kin
yu chen » yu cheng, yi chen, yulu chen
hong yu » wong yue

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: wai ((yang guang) OR (((yang liang) OR (yang yang)))) ((hua gene) OR (yu chen)) tang kia hong yu ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wai ((yang guang) or (((yang liang) OR (yang yang)))) ((hua gene) or (yu chen)) tang kia hong yu ;~".
• Adding a wildcard symbol may retrieve word variants: wai ((yang guang) or (((yang liang) OR (yang yang)))) ((hua gene) or (yu chen)) tang kia hong yu ;*.