Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
cau treo » cau theo, cau tren, cau triet
dan hang » ban hang, van hang, dat hang
thuc dan » thuc hanh, hoc dan, thuc vat
vien cac » vien bach, vien dai, vien da
cac thuc » cach thuc, cac thu, can thuc
ky lang » ky dang, ky tang, tay lang
hang di » hang doi, hang vi, hang dien
cua tre » cua te, cuu tre, cua triet
tu sach » thu sach, su sach, te sach

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

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