Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
su sach » so sach, vu sach
vai cua » dai cua, hai cua, lai cua
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
va cao » va cac, va co, va dao
luc va » duc va, tuc va
loc va » hoc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((mang may) or (nang x)) hoi. hieu va cao ((luc va) OR (loc va)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((mang may) OR (nang x)) hoi. hieu va cao ((luc va) OR (loc va)) hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((mang may) or (nang x)) hoi. hieu va cao ((luc va) OR (loc va)) hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((mang may) or (nang x)) hoi. hieu va cao ((luc va) OR (loc va)) hanh vai cua tre*.