Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cach » vien bach, vien cac, vien canh
sach ky » sach y, sach ty, sach kem
cach tu » cach thuc
ban dai » ban dan, can dai, bac dai
dai cuu » dai cua, dai huu
cuu tre » cua tre, cau tren, cau treo
sac ky » cac ky, sai ky
tu cua » hu cua, vu cua

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) OR (sac ky)) nang ((x ho) OR (xa hoi)). hieu vien cach tu cua ban dai cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) nang ((x ho) or (xa hoi)). hieu vien cach tu cua ban dai cuu tre~".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) nang ((x ho) or (xa hoi)). hieu vien cach tu cua ban dai cuu tre*.