Not really because ISIS doesn't pre-calculate an alternative path. It runs the SPF algorithm and finds the shortest path (lowest total cost) to each End System (router) and then the prefixes advertised by each of them. The database contains no routes, it describes how things are connected in ISIS (the neighbors, the prefixes, the metrics, system ids, hostnames, and so on). You might be thinking about EIGRP where there are precalculated feasible successors in the topology table. ISIS does not work that way. Nor does OSPF.
What you can do is look at the contents of the database (show isis database extensive) and basically kind of manually verify that you have all the LSPs from all the routers, and that they are advertising the ISIS neighbors and prefixes. Not an easy task for a large network. But all the show isis commands (show is route, show isis spf results, and so on) will show you only the best path.
Now, if you have equal cost path Junos places the two next hops in the routing table eventhough load balancing does not happen by default. If the selected next hop fails, the other one gets installed in the forwarding table.
VR3.inet.0: 10 destinations, 10 routes (10 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both
192.168.10.1/32 *[IS-IS/18] 00:00:15, metric 20 > to 10.10.50.1 via lt-0/0/0.3 <= only this next-hop is used. to 10.10.60.1 via lt-0/0/0.4
I hope this helps, though probably not the response you were hoping for.
Just for clarification: the IS-IS database does not contain any paths at all. It is just a source of available information to the protocol which are used by the SPF algorithms as input.
The actual result of the SPF calculation can be seen via the "show isis spf results" command. By default SPF only calculates equal cost paths to each destination (no backup paths). If you want to have backup paths, you need LFA (which requires MPLS dataplane and does not cover all topologies unless you use remote LFA).