There is no way to upload your .tax data files to TurboTax Online and store them there. There is no way to view them online. The only way to view them is with the software for the year that you want to view.
You should save your tax returns as PDFs as well as saving the .tax data files, so you can easily view them in Adobe Reader. And make backups of your .tax and PDF files on a removable storage device such as a flash drive, external hard drive, or CD, or in cloud storage. TurboTax does not have copies of them. If the hard drive on your computer fails, you will lose all your tax returns if you do not have backup copies.
