Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
hanh lai » hanh lam, hanh tai, thanh lap
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
thuc va » thuc dan, thuc day
lai cua » dai cua, hai cua, lai chau
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: toc sach thi nang cao hoi. hieu va cac ((thuc va) or (thuc vat)) hanh lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thi nang cao hoi. hieu va cac ((thuc va) OR (thuc vat)) hanh lai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach thi nang cao hoi. hieu va cac ((thuc va) or (thuc vat)) hanh lai cua tre*.