Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
hieu vien » hieu hien, hieu viec, thieu nien
thai cua » than cua, tai cuc, tri cua
van hanh » van thanh, ban hanh, van anh
duc van » duc va, duc tan, duc manh
vien da » vien dai, hien dai
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach ty, sach kem
ro hai » co hai, so hai, do hai
da duc » dao duc, da duoc, do duc
o hai » co hai, so hai, o lai

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 ky) or (sach y)) nang ((ro hai) OR (o hai)). hieu vien da duc van hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sach y)) nang ((ro hai) OR (o hai)). hieu vien da duc van hanh thai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (sach y)) nang ((ro hai) OR (o hai)). hieu vien da duc van hanh thai cua tre*".