Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien sach » vien bach, dien sach, viet sach
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
doi cua » dai cua, hoi cua, dong cua
di cua » dai cua, de cua, do cua

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