Perhaps you should try some spelling variations:
qua cham » qua hai, qua cac, va cham
cham cuc » cham cuu, pham cuc, pham chuc
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cuc ban » cua ban, cac ban, cuu ban
hanh tu » anh tu, danh tu
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
x hoi » o hoi, x ho, 5 hoi

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 ((x hoi) or (xa hoi)). hieu qua cham cuc ban hanh tu ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((x hoi) OR (xa hoi)). hieu qua cham cuc ban hanh tu ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((x hoi) or (xa hoi)). hieu qua cham cuc ban hanh tu ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) or (xa hoi)). hieu qua cham cuc ban hanh tu ((cua tre) OR (cuu tre))*.