Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, can thuc
hanh dai » hanh tai, hanh dao, vanh dai
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
cam thu » nam thu, cac thu, ca thu
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
te sai » te tai, te bai, te lai
te ban » te bao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sai) or (te ban)) ky nang cao hoi. hieu ve ((cam thuc) or (cam thu)) va hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sai) OR (te ban)) ky nang cao hoi. hieu ve ((cam thuc) OR (cam thu)) va hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sai) or (te ban)) ky nang cao hoi. hieu ve ((cam thuc) or (cam thu)) va hanh dai cua tre*.