Perhaps you should try some spelling variations:
hieu sach » chieu sach, hieu cach, dien sach
hanh hang » thanh hang, hang hang, hanh han
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, cong dong
phan cau » phan cac, phan tu, phan lap
phan dau » phan tu, hang dau
va dang » van dang, va nang, va lang

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: doc hieu sach - hanh hang va dang ((cong dan) OR (huong dan)) ((phan cau) OR (phan dau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu sach - hanh hang va dang ((cong dan) or (huong dan)) ((phan cau) OR (phan dau))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu sach - hanh hang va dang ((cong dan) or (huong dan)) ((phan cau) OR (phan dau))*.