Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
tai khoi » tai khoa, mai khoi, tao khoi
vat hanh » vat thanh, van hanh, va hanh
hanh dai » hanh tai, hanh dao, vanh dai
vu sach » vu bach, su sach, vu khach
tai hoi » dai hoi, tai hai, tai hoe
hieu ve » hieu van
hieu va » lieu va, hieu qua
y nang » ky nang, ly nang, v nang
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 y nang ((tai hoi) or (tai khoi)). ((hieu ve) or (hieu va)) tham thuc vat hanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach y nang ((tai hoi) OR (tai khoi)). ((hieu ve) OR (hieu va)) tham thuc vat hanh dai cua te.
• Adding a wildcard symbol may retrieve word variants: vu sach y nang ((tai hoi) or (tai khoi)). ((hieu ve) or (hieu va)) tham thuc vat hanh dai cua te*.