Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
sach ty » sach tu, sach thu, xach tay
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
va cham » va chat, va tham
ma hoi » mai hoi, xa hoi, ma hoa
dai va » mai va
doi va » hoi va, noi va

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach ty) OR (sach y)) nang ma hoi. hieu va cham thuc van hanh ((dai va) or (doi va)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach ty) OR (sach y)) nang ma hoi. hieu va cham thuc van hanh ((dai va) OR (doi va)) triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach ty) OR (sach y)) nang ma hoi. hieu va cham thuc van hanh ((dai va) or (doi va)) triet*".