Perhaps you should try some spelling variations:
dong hoang » hong hong
human gene » human genome, human gender, human bone
hoang yan » huang yang, wang yan, zhang yan
hua gene » a gene, hua ren, hy5 gene
thi hong » tan hong
yan thi » yan zhi, tran thi, dang thi
hong yu » wong yue

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

• Performing a fuzzy search may retrieve terms with similar spellings: dong hoang yan ((hua gene) or (human gene)) yan thi hong yu ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: dong hoang yan ((hua gene) OR (human gene)) yan thi hong yu ;*.