Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
so sach » so sanh, bo sach, co sach
hieu va » lieu va, hieu qua
cac xuc » cam xuc, cac nuoc, chat xuc
lai cua » dai cua, hai cua, lai chau
cua tre » cua te, cuu tre, cua triet
co hoi » co hoc

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 thi nang ((co loi) OR (co hoi)). hieu va cac xuc ((le thanh) or (ban thanh)) lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach thi nang ((co loi) OR (co hoi)). hieu va cac xuc ((le thanh) OR (ban thanh)) lai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach thi nang ((co loi) OR (co hoi)). hieu va cac xuc ((le thanh) or (ban thanh)) lai cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach thi nang ((co loi) OR (co hoi)). hieu va cac xuc ((le thanh) or (ban thanh)) lai cua tre*.