Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu xanh » chieu xanh, hieu manh, hieu nganh
doc hieu » toc thieu, hoc thieu, hoc hien
anh tang » anh bang, anh nang, anh sang
anh dang » anh dong, anh dung, anh bang
va thong » va thuong, va phuong, he thong
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than ban » thanh ban, toan ban, than man

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) or (anh dang)) va thong cong dan than ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - ((anh tang) OR (anh dang)) va thong cong dan than ban.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - ((anh tang) or (anh dang)) va thong cong dan than ban*.