Perhaps you should try some spelling variations:
sach tham » sach nha
thu sach » tu sach, thuat sach, thuoc sach
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
cam quoc » cac quoc, cao quoc, nam quoc
quoc ban » quoc bao, quoc lan, quoc quan
ban hanh » ban hang
hanh dai » hanh tai, hanh dao, vanh dai
mang xa » lang xa, mang may, mang cua
van cam » van nam, van lam, van cau
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: thu sach tham ((mang xa) or (dang xay)) hoi. hieu van cam quoc ban hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach tham ((mang xa) OR (dang xay)) hoi. hieu van cam quoc ban hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach tham ((mang xa) or (dang xay)) hoi. hieu van cam quoc ban hanh dai cua tre*.