Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
nhan tang » nhan dang, nham tang, nhan lang
tang luan » dung luan
luan nang » luan van, van nang, luan san
nang cong » nang song, dang cong, bang cong
san toan » van toan, manh toan, xuan toan
dan toan » van toan, dan than, manh toan

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 - nhan tang luan nang cong ((san toan) or (dan toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - nhan tang luan nang cong ((san toan) OR (dan toan)) cao*.