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