If you have defined dimensions with names (e.g. Department, Project etc) there are a couple of things you have to do in order to see then in Advanced Search.
Check you have given the dimensjons a name in the correct language column in AdminClient setupclientPosting line names.
Make the field visible in all relevant setups in AdminTransaction Setup. If the field isn't visible there, you cannot use it as a search criteria in Archive either.
Once you have made the changes, log out and in again, go to Advanced Search, choose your client and you will then see the correct dimension with its name, in the list of things you can search for.