Perhaps you should try some spelling variations:
ban thanh » ban hanh
ban hang » ngan hang
tu sach » thu sach, su sach, te sach
cay dua » chay dua, cay lua, ca dua
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
cam dua » ca dua, chay dua, cach dua
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa

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 nang ma hoi. hieu ve ((cam dua) or (cay dua)) ((ban thanh) OR (ban hang)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. hieu ve ((cam dua) OR (cay dua)) ((ban thanh) OR (ban hang)) vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoi. hieu ve ((cam dua) or (cay dua)) ((ban thanh) OR (ban hang)) vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. hieu ve ((cam dua) or (cay dua)) ((ban thanh) OR (ban hang)) vai cua tre*.