Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien dai » hien dai
dai truc » dai thuc, doan truc, dai trung
tu sach » thu sach, su sach, te sach
va nang » van nang, da nang, cam nang
va hang » van hang, va lang, va hanh
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
cua tuc » cua duc, cua thuoc, luat tuc
cua tu » cua su, cua cu, cua te

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ma hoa. hieu vien dai truc ((va hang) or (va nang)) di ((cua tu) OR (cua tuc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoa. hieu vien dai truc ((va hang) OR (va nang)) di ((cua tu) OR (cua tuc)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoa. hieu vien dai truc ((va hang) or (va nang)) di ((cua tu) OR (cua tuc))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoa. hieu vien dai truc ((va hang) or (va nang)) di ((cua tu) OR (cua tuc))*.