Perhaps you should try some spelling variations:
dong nana » dong nan, dong yang
yang yang » wang yang, wang yan
gene yang » gene bank
yang tang » nang trang, yang guang, yang liang
tang tang » taizong tang
yala hua » ya hua
hua gene » human gene, a gene, hua ren
tang hai » dang hai, shang hai, tang li

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((dong nana) or (((yang yang) or (wang yanling)))) yala hua gene yang tang tang hai ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((dong nana) OR (((yang yang) OR (wang yanling)))) yala hua gene yang tang tang hai ;.
• Adding a wildcard symbol may retrieve word variants: ((dong nana) or (((yang yang) or (wang yanling)))) yala hua gene yang tang tang hai ;*.