Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thu sach » tu sach, thuat sach, thuoc sach
qua ban » cua ban, qua quan
lai cua » dai cua, hai cua, lai chau
vai cua » dai cua, hai cua, bai cua
sach ky » sac ky, sach y, sach ty
hieu va » lieu va
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
ca qua » cau qua, cac qua, ca quan

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky sang ma hoa. ((hieu va) OR (hieu qua)) ca qua ban thanh ((vai cua) or (lai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky sang ma hoa. ((hieu va) OR (hieu qua)) ca qua ban thanh ((vai cua) OR (lai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky sang ma hoa. ((hieu va) OR (hieu qua)) ca qua ban thanh ((vai cua) or (lai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky sang ma hoa. ((hieu va) OR (hieu qua)) ca qua ban thanh ((vai cua) or (lai cua)) tre*.