Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
xa thanh » va thanh, ha thanh, ta thanh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
xay hoi » tay hoi, cay phoi, gay thoi
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cai
va cao » va cac, va co, va dao

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 dang ((xay hoi) OR (xa hoi)). hieu ((va cam) or (va cao)) tuc xa thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ((xay hoi) OR (xa hoi)). hieu ((va cam) OR (va cao)) tuc xa thanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ((xay hoi) OR (xa hoi)). hieu ((va cam) or (va cao)) tuc xa thanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((xay hoi) OR (xa hoi)). hieu ((va cam) or (va cao)) tuc xa thanh dai cua tre*.