Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
hanh thai » nhanh thai, hinh thai, hanh tai
thai cua » than cua, tai cuc, tri cua
ban hanh » ban hang
vien cao » vien cac, vien dai, vien da
duc ban » duc tan, duc van, dua ban
cao duc » dao duc, cao suc, giao duc
sach ty » sach tu, sach thu, xach tay
nang ho » nang hoc, nang co, tang ho
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ro, nang x

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ty) or (sach y)) ((nang o) OR (nang ho)) hoi. hieu vien cao duc ban hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach y)) ((nang o) OR (nang ho)) hoi. hieu vien cao duc ban hanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) or (sach y)) ((nang o) OR (nang ho)) hoi. hieu vien cao duc ban hanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) or (sach y)) ((nang o) OR (nang ho)) hoi. hieu vien cao duc ban hanh thai cua tre*.