Perhaps you should try some spelling variations:
ban thanh » ban hang
cham dua » chay dua, cham giua, pham duc
ban hanh » ban hang
toc sach » hoc sach, doc sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
cuu tre » cua tre, cau treo
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y nang ma hoa. hieu ve cham dua ((ban thanh) or (ban hanh)) lai ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ma hoa. hieu ve cham dua ((ban thanh) OR (ban hanh)) lai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang ma hoa. hieu ve cham dua ((ban thanh) or (ban hanh)) lai ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ma hoa. hieu ve cham dua ((ban thanh) or (ban hanh)) lai ((cuu tre) OR (cau tren))*.