Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
hoang van » hang va
dung cong » dung trong
tang van » dang van, trong van, tang luan
cong tan » cong tac, cong san, cong thanh
tan toan » tan tran, tap toan, van toan
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien xanh - hanh ((tang van) or (hoang van)) dung cong tan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - hanh ((tang van) OR (hoang van)) dung cong tan toan cao*.