Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
hanh dai » hanh tai, hanh dao, vanh dai
ban hanh » ban hang
quoc ban » quoc bao, quoc lan, quoc quan
dan quoc » dang quoc, han quoc, tran quoc
viec dan » viec dang, viec ban, viec dat
lang xa » lang ha, dang xay, lang van
tang ma » mang may, tang van
sach ty » sach tu, sach thu, xach tay
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: tu ((sach y) or (sach ty)) ((tang ma) or (lang xa)) hoi. hieu viec dan quoc ban hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach y) OR (sach ty)) ((tang ma) OR (lang xa)) hoi. hieu viec dan quoc ban hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach y) or (sach ty)) ((tang ma) or (lang xa)) hoi. hieu viec dan quoc ban hanh dai cua tre*.