Perhaps you should try some spelling variations:
dang xay » dang van
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
xuc van » duc van, luc van, vuc van
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao

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) or (van xay)) hoi. hieu va cam xuc van hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((dang xay) OR (van xay)) hoi. hieu va cam xuc van hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((dang xay) or (van xay)) hoi. hieu va cam xuc van hanh dai cua tre*.