Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach ty
van cau » van dau, van hau, van chat
va hanh » van hanh, va thanh, va danh
nang xa » nang x, lang xa, mang xa
tu sach » thu sach, su sach, te sach
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 ((nang xa) or (nang ma)) hoi. hieu van cau truc ((va hanh) or (ban hanh)) dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang ma)) hoi. hieu van cau truc ((va hanh) OR (ban hanh)) dai va triet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang ma)) hoi. hieu van cau truc ((va hanh) or (ban hanh)) dai va triet*.