Perhaps you should try some spelling variations:
ban thanh » ban hang
va triet » va thiet, va trien, ve triet
ban hanh » ban hang
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
cac tuc » cac toc, cac tac, cac nuoc
hieu va » lieu va, hieu qua
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
cac tu » cac thu, cach tu, cac du
dai va » mai va

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 dang xa hoi. hieu va ((cac tuc) OR (cac tu)) ((ban hanh) or (ban thanh)) dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang xa hoi. hieu va ((cac tuc) OR (cac tu)) ((ban hanh) OR (ban thanh)) dai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang xa hoi. hieu va ((cac tuc) OR (cac tu)) ((ban hanh) or (ban thanh)) dai va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang xa hoi. hieu va ((cac tuc) OR (cac tu)) ((ban hanh) or (ban thanh)) dai va triet*.