Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
hanh dai » hanh tai, hanh dao, vanh dai
nang cai » nang cao, nang cap, nang can
nang tai » hang tai, tang tai, sang tai
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
ve tham » va tham, ve cham, vi tham
hieu ve » hieu va, hieu van
sach ky » sach y, sach ty, sach kem
sac ky » cac ky, sai ky
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: vu ((sach ky) OR (sac ky)) ((nang cai) or (nang tai)) hoi. hieu ve tham thuc va hanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach ky) OR (sac ky)) ((nang cai) OR (nang tai)) hoi. hieu ve tham thuc va hanh dai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu ((sach ky) OR (sac ky)) ((nang cai) or (nang tai)) hoi. hieu ve tham thuc va hanh dai cua te".
• Adding a wildcard symbol may retrieve word variants: vu ((sach ky) OR (sac ky)) ((nang cai) or (nang tai)) hoi. hieu ve tham thuc va hanh dai cua te*.