You can't at this time.  It has been feedback that has been given to Intuit repeatedly, so hopefully we see it on the radar soon.

In Canada you don't have an option that is close, but in the US, you have the option to export your QBO file into a QB Desktop file.  That would theoretically be a backup of your QBO, but you would need a QBDT subscription to do this.

Updated: April2017