Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
cam thuc » am thuc, nam thuc, cam thu
thuc ban » thuoc ban, thuc dan, thu ban
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
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam

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 cao)) hoi. hieu ve cam thuc 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 cao)) hoi. hieu ve cam thuc ban thanh va su triet.
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang x) or (nang cao)) hoi. hieu ve cam thuc ban thanh va su triet*.