Search for a word in encrypted text

I use TripleDes and Cryptography in C# to encrypt my text and then save it in a database. Now I want to be able to search for a single word in that encrypted text in the database. I thought that if I encrypt the word I want to search on, that I can use that encrypted word to search in my database (SQL Server with FREETEXT). But the encrypted string of the word doesn't apear at all in the entire encrypted text.

How can I achieve what I want namely, a user types in a word he want to look for and my database will return the found record. Encryption must remain in .NET though. I don't know how to create the identical encryption on the database.