Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
doc hieu » toc thieu, hoc thieu, hoc hien
anh tang » anh bang, anh dang, anh nang
tang van » dang van, hoang van, trong van
ban cong » bang cong, van cong, phan cong
cong san » cong tac
toan cao » toan ban
toan tap » toan ban

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 - anh tang van ban cong san ((toan cao) or (toan tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - anh tang van ban cong san ((toan cao) OR (toan tap)).
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - anh tang van ban cong san ((toan cao) or (toan tap))*.