Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
van hanh » van thanh, ban hanh, van anh
vien cac » vien bach, vien dai, vien da
sach ky » sac ky, sach y, sach ty
hanh ve » hanh vi, hanh va, hanh kem
toc van » hoc van, toc san, tac van
cac toc » cac toi, cac nuoc, cac thoi
su sach » so sach, vu sach
lang xa » lang ha, dang xay, lang van
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, mang xa, ang xa
su hien » su kien, su tien, thu hien
ve su » va 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 sach ky ((((nang xa) OR (nang ma))) or (lang xa)) hoi. hieu vien cac toc van hanh ve su hien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((((nang xa) OR (nang ma))) OR (lang xa)) hoi. hieu vien cac toc van hanh ve su hien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((((nang xa) OR (nang ma))) or (lang xa)) hoi. hieu vien cac toc van hanh ve su hien".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((((nang xa) OR (nang ma))) or (lang xa)) hoi. hieu vien cac toc van hanh ve su hien*.