With TortoiseSVN you can browse folders inside one repository only. Although you can browse list repositories provided by VisualSVN Server in a web browser, you cannot browse repository list with TortoiseSVN (or any other Subversion client) because Subversion protocol doesn't support listing repositories. If you try accessing https://yoursvnserver/svn/ via TortoiseSVN you should get an error "Server sent unexpected return value (405 method not allowed) in response to PROPFIND request for '/svn'".
Please note that it's recommended to store all projects in one repository instead of creating separate repository for each project.
