Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
vai cua » dai cua, hai cua, lai cua
van cac » van hac, van cau, van bac
cua tre » cua te, cuu tre, cua triet
xang xa » lang xa, mang xa, dang xay
ang xa » lang xa, mang xa, dang xay
xac va » tac va, ac va, bac va
luc va » duc va, tuc va, loc va

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 thu ((xang xa) OR (ang xa)) hoi. hieu van cac ((xac va) or (luc va)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach thu ((xang xa) OR (ang xa)) hoi. hieu van cac ((xac va) OR (luc va)) hanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach thu ((xang xa) OR (ang xa)) hoi. hieu van cac ((xac va) or (luc va)) hanh vai cua tre*".