Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
tang ma » mang may, tang van
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
ma hoi » mai hoi, xa hoi, me hoi
vi hoa » voi hoa, vi hoc, va hoa

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 ky tang ma hoi. hieu ve cham thuc van hanh ((vi hoa) or (((van hoa) or (ma hoa)))) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang ma hoi. hieu ve cham thuc van hanh ((vi hoa) OR (((van hoa) OR (ma hoa)))) viet.
• Adding a wildcard symbol may retrieve word variants: su sach ky tang ma hoi. hieu ve cham thuc van hanh ((vi hoa) or (((van hoa) or (ma hoa)))) viet*.