Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
mong luan » tong luan, cong luan, dong luan
bang luan » tang luan, hang luan, dung luan
dong cong » duong cong, dang cong, cong cong
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan tap

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh ((mong luan) OR (bang luan)) ((dong cong) OR (dung cong)) dan toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - hanh ((mong luan) or (bang luan)) ((dong cong) OR (dung cong)) dan toan cau~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh ((mong luan) or (bang luan)) ((dong cong) OR (dung cong)) dan toan cau*.