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 triet » su viet, su tien, ve triet
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
cac toc » cac toi, cac nuoc, cac thoi
toc van » hoc van, toc san, tac van
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky ((nang xa) or (nang ma)) hoi. hieu vien cac toc van hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky ((nang xa) OR (nang ma)) hoi. hieu vien cac toc van hanh vi su triet.
• Adding a wildcard symbol may retrieve word variants: su sac ky ((nang xa) or (nang ma)) hoi. hieu vien cac toc van hanh vi su triet*.