Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh va » thanh van, hanh va, thanh ha
su sach » vu sach
cam dua » ca dua, cay dua, chay dua
so sach » so sanh, bo sach, co sach
ty hang » ly hang, ty xang, thi hang
dua ban » dia ban, cua ban, qua ban
qua cam » qua cham, qua cac, qua ca
va cua » va chua, via cua, ca cua
cua te » cua tu
ca hoi » cau hoi, cua hoi, co hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sach)) ty hang ((ca hoi) OR (xa hoi)). hieu qua cam dua ban thanh va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ty hang ((ca hoi) OR (xa hoi)). hieu qua cam dua ban thanh va cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ty hang ((ca hoi) OR (xa hoi)). hieu qua cam dua ban thanh va cua te".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ty hang ((ca hoi) OR (xa hoi)). hieu qua cam dua ban thanh va cua te*.