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