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
cac toi » cac thoi
toi van » thi van, tri van, doi van
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho
vi ve » va ve, gi ve, vi he
ve ve » de ve, va ve, ve ke
ke ve » ke va, ke he, de ve

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 y nang x hoi. hieu vien cac toi van hanh ((vi ve) or (((ve ve) or (ke ve)))) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x hoi. hieu vien cac toi van hanh ((vi ve) OR (((ve ve) OR (ke ve)))) triet.
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. hieu vien cac toi van hanh ((vi ve) or (((ve ve) or (ke ve)))) triet*.