Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
hanh thai » nhanh thai, hinh thai, hanh tai
vien cac » vien bach, vien dai, vien da
thai cua » than cua, tai cuc, tri cua
duc van » duc va, duc tan, duc manh
xuc ban » duc ban, cuc ban, quoc ban
sach ky » sach y, sach ty, sach kem
nang ho » nang hoc, nang co, tang ho
cua tre » cua te, cuu tre, cua triet
ho hai » hoc hai, pho hai, cho hai
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sac ky)) nang ho hai. hieu vien cac ((xuc ban) or (duc van)) hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang ho hai. hieu vien cac ((xuc ban) OR (duc van)) hanh thai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) nang ho hai. hieu vien cac ((xuc ban) or (duc van)) hanh thai cua tre*.