Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
bach du » bach dieu, bach hue, bach nhu
va hanh » va thanh, va danh, ban hanh
ma hoi » xa hoi, ma hoa, me hoi
vi cua » vai cua, di cua
cua te » cua tu

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 ky nang ((ma hoi) or (mai hoi)). hieu vien bach du ((va hanh) OR (van hanh)) vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((ma hoi) OR (mai hoi)). hieu vien bach du ((va hanh) OR (van hanh)) vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((ma hoi) or (mai hoi)). hieu vien bach du ((va hanh) OR (van hanh)) vi cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((ma hoi) or (mai hoi)). hieu vien bach du ((va hanh) OR (van hanh)) vi cua te*.