Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
cac thu » cach thuc, cac thoi
va hanh » va thanh, va danh, ban hanh
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
vi cua » vai cua, di cua
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ly nang o hoi. hieu vien cac thu ((va hanh) or (van hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang o hoi. hieu vien cac thu ((va hanh) OR (van hanh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ly nang o hoi. hieu vien cac thu ((va hanh) or (van hanh)) vi cua tre*.