Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
va triet » va thiet, va trien, ve triet
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
tuc van » thuc van, truc van, tuc va
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
hieu ve » hieu van
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
cac tuc » cac toc, cac tu, cac tac

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 ve) or (hieu va)) cac tuc van hanh tai ((va triet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang xa hoi. ((hieu ve) OR (hieu va)) cac tuc van hanh tai ((va triet) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang xa hoi. ((hieu ve) or (hieu va)) cac tuc van hanh tai ((va triet) or (su triet))*.