Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh va » thanh van, hanh va, thanh ha
su triet » su viet, su tien, ve triet
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
cam tuc » cam tu, nam thuc, dam thuc

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky ((nang x) or (nang ma)) hoi. hieu ve ((cam tuc) OR (cam xuc)) ban thanh va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang x) OR (nang ma)) hoi. hieu ve ((cam tuc) OR (cam xuc)) ban thanh va su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky ((nang x) or (nang ma)) hoi. hieu ve ((cam tuc) OR (cam xuc)) ban thanh va su triet".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang x) or (nang ma)) hoi. hieu ve ((cam tuc) OR (cam xuc)) ban thanh va su triet*.