Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
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
doc hieu » toc thieu, hoc thieu, hoc hien
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: doc hieu xanh - nhan tang luan nang cong ((san toan) OR (dan toan)) cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - nhan tang luan nang cong ((san toan) OR (dan toan)) cao*".