Perhaps you should try some spelling variations:
ban thanh » ban hang
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
cua tre » cua te, cuu tre, cua triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cam qua » cau qua, cac qua, cay qua
van cam » van nam, van lam, van cau
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang

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

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