Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
doc hieu » toc thieu, hoc thieu, hoc hien
canh van » anh van, can van, cach van
cua dang » cua cong
cong van » cong vang, cong san, song van
than cau » toan cau, phan cau, thanh chau
than cap » khan cap, thanh lap, thanh cac

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 - canh van ((cua dang) OR (cua ban)) cong van ((than cau) OR (than cap))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - canh van ((cua dang) or (cua ban)) cong van ((than cau) OR (than cap))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - canh van ((cua dang) or (cua ban)) cong van ((than cau) OR (than cap))*.