Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
sach thu » sach thieu, sach tham, cach thuc
hanh vai » hanh vi, hanh va, hanh tai
vai cua » dai cua, hai cua, lai cua
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
cao hoi » cau hoi, co hoi, cao hoc
cua tre » cua te, cuu tre, cua triet
do va » do van
so va » so van, so vat, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach thu) or (sach thue)) nang cao hoi. hieu ve cham ((do va) OR (so va)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach thu) OR (sach thue)) nang cao hoi. hieu ve cham ((do va) OR (so va)) hanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach thu) or (sach thue)) nang cao hoi. hieu ve cham ((do va) OR (so va)) hanh vai cua tre*".