Hi,
If you're searching with parameters, make sure that the parameter type is NVarChar or NChar which accepts unicode. Or the search will not return good results.
HTH. If this does not answer your question, please feel free to mark the post as Not Answered and reply. Thank you!
Sincerely,
Kevin Yu
Microsoft Online Community Support
Please remember to click “Mark as Answer” on the post that helps you, and to click “Mark as Not Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.