Perhaps you should try some spelling variations:
ban hang » ngan hang
su triet » su tien, ve triet
su sach » so sach, vu sach
hieu du » hien du, hieu su, hiem du
su viet » so viet
y nang » ky nang, ly nang, v nang
du cam » tu cam, xu cam, dung cam
x hoi » xa hoi, o hoi, x ho

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 y nang x hoi. hieu du cam xuc ((van ban) or (ban hang)) ve ((su triet) OR (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x hoi. hieu du cam xuc ((van ban) OR (ban hang)) ve ((su triet) OR (su viet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x hoi. hieu du cam xuc ((van ban) or (ban hang)) ve ((su triet) OR (su viet))*".