If you haven't already, make a deconstruction table or 2 or 4, and drop in crafting tables, wool, or natura berries (if you have a lot). You will get lots of primal aspects from them. You have to click the deconstruction tables to get the research point. Also, if you create items you have researched, you often get several of the aspects back.
You can also go around and scan a bunch of nodes.
If you set the thaumcraft difficulty to hard, you have to play the mini game every time, but you also get to choose the aspects you consume to solve the puzzle. This lets you take different paths to solve them thereby saving the primals until you need them.
I have done almost all the research, and have not built a deconstruction table, and I have never run out of aspects. Although, I did get low enough that I had to stop researching and build some of the stuff before I could continue.