Perhaps you should try some spelling variations:
nhieu viec » nhien viet
hieu viec » hieu ve, sieu viet, hieu hien
cac thuc » cach thuc, cac thu, can thuc
dan hang » ban hang, van hang, dat hang
thuc dan » thuc hanh, hoc dan, thuc vat
cua tre » cua te, cua triet, dua tren
hang di » hang doi, hang vi, hang dien
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cuu tre » cau tren, cau treo

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 ky lang xa hoi. ((hieu viec) OR (nhieu viec)) cac thuc dan hang di ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang xa hoi. ((hieu viec) OR (nhieu viec)) cac thuc dan hang di ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang xa hoi. ((hieu viec) OR (nhieu viec)) cac thuc dan hang di ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang xa hoi. ((hieu viec) OR (nhieu viec)) cac thuc dan hang di ((cua tre) or (cuu tre))*.