Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu xanh » chieu xanh, hieu manh, hieu nganh
doc hieu » toc thieu, hoc thieu, hoc hien
kha dung » khoa dung, khao dung, nha dung
cong van » cong vang, cong san, song van
toan cao » toan tap
toan ban » van ban
ha dung » hai dung, nha dung, ha dong

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 - thanh trung ((ha dung) OR (kha dung)) cong van ((toan cao) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - thanh trung ((ha dung) or (kha dung)) cong van ((toan cao) OR (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - thanh trung ((ha dung) or (kha dung)) cong van ((toan cao) OR (toan ban))*.