Trade routes to other civilizations can give science beakers when the other civ knows more techs.
How many depends on how many techs ahead the civ is, but in the later eras this bonus becomes useless...
If you are 8 techs behind you get 4 science beakers from the trade route, which is significant at the start of the game but as the game progresses the techs get a lot more expensive and the bonus doesn't change.
So, IMO the science bonus should scale with the ages. This should help civs keep up
How many depends on how many techs ahead the civ is, but in the later eras this bonus becomes useless...
If you are 8 techs behind you get 4 science beakers from the trade route, which is significant at the start of the game but as the game progresses the techs get a lot more expensive and the bonus doesn't change.
So, IMO the science bonus should scale with the ages. This should help civs keep up