Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cao » vien cac, vien dai, vien da
thuc van » thuc vat, thuc dan, thuc va
cao thuc » cao thuoc, bao thuc, can thuc
su sach » so sach, vu sach
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
cua tre » cua te, cuu tre, cua triet
anh vi » hanh vi, anh ve, anh vu
anh va » hanh va

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: su sach ((ty nang) OR (ty hang)) xa hoi. hieu vien cao thuc van ((anh vi) OR (anh va)) cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) or (ty hang)) xa hoi. hieu vien cao thuc van ((anh vi) OR (anh va)) cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty nang) or (ty hang)) xa hoi. hieu vien cao thuc van ((anh vi) OR (anh va)) cua tre*.