Perhaps you should try some spelling variations:
hieu vien » hieu viec, thieu nien, hieu tieng
hieu hien » bieu hien, dieu hien, chieu chien
cac thoi » cac toi, cac tro, cac thu
san hanh » san thanh, ban hanh, van hanh
ve triet » va trien, su triet
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
vi ve » va ve, gi ve, ve ve

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky nang xa hoi. ((hieu vien) OR (hieu hien)) ((cac thoi) or (cac hop)) san hanh vi ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang xa hoi. ((hieu vien) OR (hieu hien)) ((cac thoi) OR (cac hop)) san hanh vi ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang xa hoi. ((hieu vien) OR (hieu hien)) ((cac thoi) or (cac hop)) san hanh vi ve triet".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang xa hoi. ((hieu vien) OR (hieu hien)) ((cac thoi) or (cac hop)) san hanh vi ve triet*.