Perhaps you should try some spelling variations:
cong thanh » dong thanh, cong trinh, cong tan
hieu tach » hieu cach, chiet tach, chieu sach
tranh cua » doanh cua, manh cua
cua nhung » va nhung
cong manh » cong danh, duong manh, hoang manh
doc hieu » toc thieu, hoc thieu, hoc hien
toan ban » van ban

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu tach - canh tranh cua nhung ((cong manh) OR (cong thanh)) toan ban~".
• Adding a wildcard symbol may retrieve word variants: doc hieu tach - canh tranh cua nhung ((cong manh) OR (cong thanh)) toan ban*.