Perhaps you should try some spelling variations:
ban thanh » ban hang
cau treo » cau theo, cau tren, cau triet
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
cay qua » cau qua, cac qua, cay lua
van cay » van cau, van bay, van ca
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
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: su sach ty nang ma hoi. hieu van cay qua ((ban thanh) OR (ban hanh)) vai ((cua tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ma hoi. hieu van cay qua ((ban thanh) OR (ban hanh)) vai ((cua tre) OR (cau treo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ma hoi. hieu van cay qua ((ban thanh) OR (ban hanh)) vai ((cua tre) or (cau treo))".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ma hoi. hieu van cay qua ((ban thanh) OR (ban hanh)) vai ((cua tre) or (cau treo))*.