Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
hanh tai » thanh tai, hang tai, han tai
xa hanh » xa thanh, xa khanh, va hanh
cac tac » cac toc, cac bac, cac dac
cac tuc » cac toc, cac tu, cac nuoc
cuc tre » duc tre, cua tre, cuu tre
sach ty » sach tu, sach thu, xach tay
va hoi » xa hoi, va hoc, va hoa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: co ((sach ty) or (sach y)) hang va hoi. hieu viec ((cac tuc) OR (cac tac)) xa hanh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co ((sach ty) OR (sach y)) hang va hoi. hieu viec ((cac tuc) OR (cac tac)) xa hanh tai cuc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "co ((sach ty) or (sach y)) hang va hoi. hieu viec ((cac tuc) OR (cac tac)) xa hanh tai cuc tre".
• Adding a wildcard symbol may retrieve word variants: co ((sach ty) or (sach y)) hang va hoi. hieu viec ((cac tuc) OR (cac tac)) xa hanh tai cuc tre*.