Perhaps you should try some spelling variations:
ban hang » ngan hang
dang xay » dang van, van xay
su sach » vu sach
cau duc » cao duc, cau luc, chu duc
hieu ke » hieu kem, chieu ke, hieu ky
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet
ke cau » ket cau
de cua » le cua, te cua, dieu cua

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: ((su sach) OR (so sach)) ky dang xay hoi. hieu ke cau duc ((ban hanh) OR (ban hang)) de cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ky dang xay hoi. hieu ke cau duc ((ban hanh) OR (ban hang)) de cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky dang xay hoi. hieu ke cau duc ((ban hanh) OR (ban hang)) de cua tre*.