Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
hieu hien » bieu hien, dieu hien, chieu chien
su triet » su viet, su tien, ve triet
hoc viet » hoc hien
sach ky » sac ky, sach y, sach ty
hoc vat » hoc va, thuc vat
nang xa » nang x, lang xa, nang ma
su sach » so sach, vu sach
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 sach ky nang xa hoi. ((hieu hien) or (hieu viec)) cac ((hoc vat) OR (hoc viet)) hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. ((hieu hien) OR (hieu viec)) cac ((hoc vat) OR (hoc viet)) hanh vi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. ((hieu hien) or (hieu viec)) cac ((hoc vat) OR (hoc viet)) hanh vi su triet".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. ((hieu hien) or (hieu viec)) cac ((hoc vat) OR (hoc viet)) hanh vi su triet*.