Bought this is one of the sales quite awhile back but am just now giving it a serious try.  Went through all the tutorials and started a game.   My question is regarding technology research.    It would appear (unless I am wrong) that in spite of there being a number of different tech tabs/trees, i.e. military, industrial, etc.,  you can only ever have one item being researched at any given time, not one in each tab/tree, jsut one in total.   Is this correct?  This would seem quite restrictive, but maybe it was meant to be that way. 

Yes, that is correct, one at a time. Research is so slow compared to other games (like Civilization) but it forces you to make some hard choices.

Thanks....I suspected that was the case.  I'm not that far into the game yet (playing USA) but can already see what you mentioned, that the impact of your decisions play out long after they are made.