Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
sach dao » lanh dao
vai cua » dai cua, hai cua, lai cua
chuc va » thuc va
van cau » van dau, van hau, van chat
sach ly » sach y, sach lo, sach ty
vang xa » lang xa, mang xa, ang xa
cua tre » cua te, cuu tre, cua triet

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 ly) or (sach dao)) vang xa hoi. hieu van cau ((thuc vat) or (chuc va)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ly) OR (sach dao)) vang xa hoi. hieu van cau ((thuc vat) OR (chuc va)) hanh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ly) or (sach dao)) vang xa hoi. hieu van cau ((thuc vat) or (chuc va)) hanh vai cua tre*.