Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
vanh dai » van dai, vanh tai, lanh dao
hanh dai » hanh tai, hanh dao, thanh dat
phat day » phap day, phan day, phan dau
van phat » va phat, van chat, van phan
sach ty » sach y, sach tu, sach thu
day van » day va, dao van, duy van
mang xa » lang xa, mang may, dang xay
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: hoc sach ty ((mang xa) or (ang xa)) hoi. hieu van phat day van ((hanh dai) OR (vanh dai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ty ((mang xa) OR (ang xa)) hoi. hieu van phat day van ((hanh dai) OR (vanh dai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ty ((mang xa) or (ang xa)) hoi. hieu van phat day van ((hanh dai) OR (vanh dai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach ty ((mang xa) or (ang xa)) hoi. hieu van phat day van ((hanh dai) OR (vanh dai)) cua tre*.