Perhaps you should try some spelling variations:
ban thanh » ban hang
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
su triet » su viet, su tien, ve triet
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
van bac » van ban, van bao, van hac
te sac » te sach, te san
te cac » tu cac, ve cac, te cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sac) OR (te cac)) ky tang xa hoi. hieu van bac duc ((ban thanh) or (ban hanh)) va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sac) OR (te cac)) ky tang xa hoi. hieu van bac duc ((ban thanh) OR (ban hanh)) va su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sac) OR (te cac)) ky tang xa hoi. hieu van bac duc ((ban thanh) or (ban hanh)) va su triet".
• Adding a wildcard symbol may retrieve word variants: ((te sac) OR (te cac)) ky tang xa hoi. hieu van bac duc ((ban thanh) or (ban hanh)) va su triet*.