Perhaps you should try some spelling variations:
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
phat day » phap day, phan day, phan dau
van phat » va phat, van chat, van phan
hieu van » hieu va, thien van, lieu va
day van » day va, dao van, duy van
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, xach tay
xang xa » lang xa, mang xa, dang xay
ang xa » lang xa, mang xa, dang xay

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) OR (sach thu)) ((xang 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) OR (sach thu)) ((xang xa) OR (ang xa)) hoi. hieu van phat day van hanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach ty) OR (sach thu)) ((xang 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) OR (sach thu)) ((xang xa) or (ang xa)) hoi. hieu van phat day van hanh dai cua tre*.