I am not sure if things are supposed to keep recycling at hte maximum research or not...
I kept having research hit 97-99% and never 'finish'.
I wasnt sure if this meant I was getting mini bonuses for 'still researching' something or not.
However when I researched Civilization for a bit.. to get the prestige bonus the progress bar went all whacky
http://screencast.com/t/lxLFrQLGk
When I selected another research item, civilization went away and was no longer available to research.