Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
manh trung » manh tung, thanh trung, manh hung
hieu sach » chieu sach, hieu cach, dien sach
trung cua » truong cua, trung tuan, trung cap
tong cong » trong cong, cong cong, dung cong
doc hieu » toc thieu, hoc thieu, hoc hien
ban hanh » ban hang
ban cao » bao cao, ban can, ban co

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 - manh trung cua ((nhung cong) OR (tong cong)) vang ((ban cao) OR (ban hanh))~.
• Adding a wildcard symbol may retrieve word variants: doc hieu sach - manh trung cua ((nhung cong) or (tong cong)) vang ((ban cao) or (ban hanh))*.