Perhaps you should try some spelling variations:
hieu vien » hieu viec, thieu nien, hieu tieng
hieu hien » bieu hien, dieu hien, chieu chien
van hanh » van thanh, ban hanh, van anh
ve triet » va trien, su triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
dai thi » dan thi, tai thi, dam thi
dao thi » do thi, dan thi, dang thi
hanh ve » hanh vi, hanh va, hanh kem
ve ve » de ve, va ve, ke ve

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) or (hieu hien)) ((dai thi) OR (dao thi)) van hanh ve ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. ((hieu vien) OR (hieu hien)) ((dai thi) OR (dao thi)) van hanh ve ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. ((hieu vien) or (hieu hien)) ((dai thi) OR (dao thi)) van hanh ve ve triet".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. ((hieu vien) or (hieu hien)) ((dai thi) OR (dao thi)) van hanh ve ve triet*.