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

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