Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
duc manh » suc manh, duc anh, duc minh
hanh tai » thanh tai, hang tai, han tai
tu sach » thu sach, su sach, te sach
nang ho » nang hoc, nang co, tang ho
duc ban » duc tan, dua ban, duc man
duc van » duc va, duc tan, duc phan
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ho hai » hoc hai, pho hai, cho hai

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 y nang ho hai. hieu vien cac ((duc ban) or (((duc van) or (duc manh)))) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ho hai. hieu vien cac ((duc ban) OR (((duc van) OR (duc manh)))) hanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ho hai. hieu vien cac ((duc ban) or (((duc van) or (duc manh)))) hanh tai cua tre*.