Familysearch.org has a 7,000,000 names in their database of Norway Baptisms (probably includes spelling variations and parents' names). Downside is that not every record is perfectly identified as to which church or the page or entry number. Does not include every parish....
Check at the Digitalarkivet for Kyrkebøker or Church Registers for seperate indexes for each kind of pastoral act. There are good sets of these for Trondhjem, Bergen and a few other places and lots of odds and ends.
But diving in is the norm for most of the church books for the majority of places and turning page by page.
I have found though that searching in FamilySearch.org first is sometimes a helpful first step. They have already indexed many - but not all areas or years yet - Norwegian parish records and if you find an index entry for the name(s) you seek they will give a specific date that you can then turn the digitized pages to find the actual source document quite quickly.
You can also check the databases available for your district/parish of specific interest at Digitalarkivet. For some districts extra databases beyond the censuses have been submitted to that website for records of the area - sometimes databases of baptisms, deaths, marriages or other local events. Those databases also can serve as helpful to find the actual source document in the online scans collection.
That the Norwegian digitized parish registers are offered to us online FREELY is a marvelous gift. We all appreciate it.