Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
nang tai » hang tai, sang tai, nang cao
hanh dai » hanh tai, hanh dao, vanh dai
tang tai » hang tai, dung tai, sang tao
hieu loi » hieu moi, hien loi, hieu voi
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
hieu vi » hieu voi, hieu va, hieu ve
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
cua te » cua tu

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 ((nang tai) OR (tang tai)) hoi. ((hieu vi) or (hieu loi)) tham thuc va hanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang tai) OR (tang tai)) hoi. ((hieu vi) OR (hieu loi)) tham thuc va hanh dai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang tai) OR (tang tai)) hoi. ((hieu vi) or (hieu loi)) tham thuc va hanh dai cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang tai) OR (tang tai)) hoi. ((hieu vi) or (hieu loi)) tham thuc va hanh dai cua te*.