Perhaps you should try some spelling variations:
dung phuong » dung thuong, bang phuong, dung chung
phuong dan » phuong danh, phuong doan, huong dan
hieu xanh » chieu xanh, hieu manh, hieu nganh
doc hieu » toc thieu, hoc thieu, hoc hien
tranh su » trinh su, trang su, tranh cua
than cau » toan cau, than cap, thanh chau
phan cau » phan dau, phan cac, phan tu

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 su dung phuong dan ((than cau) or (phan cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - canh tranh su dung phuong dan ((than cau) OR (phan cau)).
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - canh tranh su dung phuong dan ((than cau) or (phan cau))*.