Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
van hanh » van thanh, ban hanh, van anh
vien cac » vien bach, vien dai, vien da
sach ky » sac ky, sach y, sach kem
xuc van » duc van, luc van, xuc ban
cac xuc » cam xuc, cac nuoc, chat xuc
mai hoi » mai khoi, dai hoi, lai hoi
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di 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: te ((sach ky) OR (sach ty)) nang ((ma hoa) OR (mai hoi)). hieu vien cac xuc van hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) OR (sach ty)) nang ((ma hoa) or (mai hoi)). hieu vien cac xuc van hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) OR (sach ty)) nang ((ma hoa) or (mai hoi)). hieu vien cac xuc van hanh vi cua tre*.