Can I continue to harvest dragon souls after the main quest is over?

I want to make sure I learn all the Thu'um, and in order to do that, I need to acquire quite a few dragon souls. Should I put off the main quest as I slay dragons and find hidden draconic words, or is this a non-issue?

Clarification: I know the dragons begin spawning after a set point in the main quest. The main crux of my question is whether they stop spawning after another (later) set point in the main quest. There are infinite dragons during the main quest, but do they stick around forever?

Solution 1:

Post main quest dragons still spawn at least for the bounty quests given by stewards. I came across a couple out in the wild but in previously undiscovered locations so no guarantees they will still random spawn.

Edit: Scratch that, just got an unpleasant surprise in riften they still spawn everywhere.

Solution 2:

Yes, there are an infinite number of random quests to do after you done the main story line. So, the game doesn't end there. The ability to harvest dragon souls has nothing to do with quests, it only has to do with killing the dragons (there are infinite of them). Some say that being near the dragon, or being involved into the fight from a distance might even be enough to obtain the dragon soul...

Given that there are 24 shouts each consisting of 3 words, you have to kill a maximum of 72 dragons to obtain all the words. Please note that some quests reward you with a shout, in which way you require to kill less dragons as the words would already be learned/activated for the other shouts. I think it would be something around 48 dragons or so, but it depends on what you were rewarded using the main quest. So, you might want to consider to continue on the main quest...

Solution 3:

The dragons never stop spawning. You can easily test this by just travelling to various dragon nests, you can kill dragons at those spots over and over again. No idea on what the respawn timer is.

There are a few named dragons that I don't think respawn, they are patrolling.