Perhaps you should try some spelling variations:
chung cong » chong cong, phung cong, chung thong
nhung cong » dung cong, thong cong, hang cong
hieu xanh » chieu xanh, hieu manh, hieu nganh
doc hieu » toc thieu, hoc thieu, hoc hien
anh dung » anh dong, anh huong, sach dung
tac than » tac thanh, tam than, tac nhan
than cau » toan cau, phan cau, than cap

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 dung luan ((chung cong) or (nhung cong)) tac than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - anh dung luan ((chung cong) OR (nhung cong)) tac than cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - anh dung luan ((chung cong) or (nhung cong)) tac than cau*.