Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
san hanh » san thanh, ban hanh, van hanh
ve triet » va trien, su triet
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach ty
cac toc » cac toi, cac nuoc, cac thoi
nang xa » nang x, lang xa, mang xa
vu sach » vu bach, su sach, vu khach
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) OR (nang ma)) hoi. hieu vien ((cac toc) 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) OR (nang ma)) hoi. hieu vien ((cac toc) 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) OR (nang ma)) hoi. hieu vien ((cac toc) or (cac hop)) san hanh vi ve triet".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang xa) OR (nang ma)) hoi. hieu vien ((cac toc) or (cac hop)) san hanh vi ve triet*.