Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
so sach » so sanh, bo sach, co sach
vai cua » dai cua, hai cua, lai cua
sach tu » sach thu, cach tu, sach ty
hieu ve » hieu va, hieu van
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach tu ((nang xa) OR (lang xa)) hoi. hieu ve cac ((duc va) or (tuc xa)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach tu ((nang xa) OR (lang xa)) hoi. hieu ve cac ((duc va) OR (tuc xa)) hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach tu ((nang xa) OR (lang xa)) hoi. hieu ve cac ((duc va) or (tuc xa)) hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach tu ((nang xa) OR (lang xa)) hoi. hieu ve cac ((duc va) or (tuc xa)) hanh vai cua tre*.