Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van phat » va phat, van chat, van phan
phat day » phap day, phan day, phan dau
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
sach ty » sach y, sach tu, sach thu
mang xa » lang xa, mang may, dang xay
day van » day va, dao van, duy van
cua tre » cua te, cuu tre, cua triet
ang xa » lang xa, dang xay, hoang xa

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 ty ((mang xa) or (ang xa)) hoi. hieu van phat day van hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty ((mang xa) OR (ang xa)) hoi. hieu van phat day van hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ty ((mang xa) or (ang xa)) hoi. hieu van phat day van hanh dai cua tre*.