Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
ban thanh » ban hanh, ban hang
su triet » su viet, ve triet
tu sach » thu sach, su sach, te sach
cuc ban » cua ban, cac ban, cuu ban
nam cuc » nam cac, nam cua, nam thuc
sach ky » sac ky, sach y, sach ty
hieu ha » hieu hoa, hieu va, hieu ca
nang ma » tang ma, sang ma, mang may
su tien » su kien, su hien, tu tieng

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: tu sach ky ((nang ma) OR (nang cao)) hoi. hieu ha nam cuc ban thanh dai ((su triet) OR (su tien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang ma) or (nang cao)) hoi. hieu ha nam cuc ban thanh dai ((su triet) OR (su tien))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang ma) or (nang cao)) hoi. hieu ha nam cuc ban thanh dai ((su triet) OR (su tien))*.