Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
thanh va » thanh van, hanh va, thanh ha
tu sach » thu sach, su sach, te sach
cuu tre » cua tre, cau tren, cau treo
y sang » _ sang, duy sang
ma hoi » mai hoi, xa hoi, me hoi
va toc » va doc, va tuc, va ton
va tac » va cac
va cuu » va cau, va chu, va huu
gia » giao

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 sang ((ma hoi) or (ma hoa)). hieu viec ((va toc) OR (va tac)) gia thanh va cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y sang ((ma hoi) OR (ma hoa)). hieu viec ((va toc) OR (va tac)) gia thanh va cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y sang ((ma hoi) or (ma hoa)). hieu viec ((va toc) OR (va tac)) gia thanh va cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y sang ((ma hoi) or (ma hoa)). hieu viec ((va toc) OR (va tac)) gia thanh va cuu tre*.