Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
thanh tung » thanh cong
hieu manh » chieu xanh, hieu nganh, dieu hanh
tong cong » trong cong, cong cong, dung cong
tung cua » trung cua, tuong cua, dung cua
cua tong » cua cong, cua dong, cua nong
san toan » van toan, manh toan, xuan toan
dan toan » van toan, dan than, manh toan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu manh) OR (chieu sach)) - thanh tung cua tong cong ((san toan) OR (dan toan)) cau~.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) or (chieu sach)) - thanh tung cua tong cong ((san toan) or (dan toan)) cau*.