Is there web-site where i can upload document that will be readable but not downloadable?
No. When you upload a document to a server, a copy of that
document is saved on another machine, but in order to read that
copy, it must be copied to the client's machine, and that means the
document must be downloadable. However, the download need not be in
the exact same format as the original document because a server can
re-encode (or convert) the uploaded document as it is being
uploaded to the server and/or as it is being downloaded to the
clients. Streaming media is an example of this. With appropriate
software a client can still save the download, but that download
will only be an exact duplicate of your upload if the server did
not re-encode the document in some way.