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