Perhaps you should try some spelling variations:
dong yang » dong hoang, dan yang, dong jung
yang yang » wang yan
wang yang » wang yan, wang liang, wang yanling
shang hai » shang kai, dang hai, chang ha
hua gene » human gene, hua ren, hy5 gene
hong hai » zhong tai, dang hai, hong tan
a gene » a genre, a gender, a gentle

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 yang yang ((hua gene) OR (a gene)) wang yang ((hong hai) OR (shang hai)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "dong yang yang ((hua gene) or (a gene)) wang yang ((hong hai) OR (shang hai)) ;~".
• Adding a wildcard symbol may retrieve word variants: dong yang yang ((hua gene) or (a gene)) wang yang ((hong hai) OR (shang hai)) ;*.