Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
cach dung » sach dung, cach mang, tac dung
cac duong » cau duong, cac tuong, cac dong
nguoi dao » nguoi tay
doc hieu » toc thieu, hoc thieu, hoc hien
cac dung » tac dung, cac dang, cac ung
dao than » dao thanh, dan than, dao thai
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 - canh tranh ((((cac dung) or (cach dung))) or (cac duong)) nguoi dao than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - canh tranh ((((cac dung) OR (cach dung))) OR (cac duong)) nguoi dao than cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - canh tranh ((((cac dung) or (cach dung))) or (cac duong)) nguoi dao than cau*.