Well, if you're looking at the military and social numbers while you're only building one of either a ship or an improvement, then the numbers won't add up.  The numbers in parentheses aren't actual production numbers, they're raw production numbers.  They don't take into account racial bonuses, and they also fail to align with funding levels because unused social is filtered to military, if military is funded.

Secondly: Social numbers -always- look funny-because it's filtered to funded military, it sort of counts as always-on, if it's funded.  If it's not building something, it's dark orange, almost greyed out, and the numbers are essentially irrelevant, except for the fact that it's included in the current military count.  If it's lit up orange, though, then it's building something, and the numbers do matter.  Military has the same lighting scheme, but shows in parentheses when it's not being used, so it's somewhat less confusing.

In general, you make the most efficient use of your resources doing either one or the other.  The ideal points for doing both simultaneously are, depending on your goals, 25/75, 50/50, and 75/25, although 1/99 (1% military, 99% social) is widely used due to the above rule of unused social being filtered to funded military.  Due to truncation, it loses a bit here and there, but more importantly, a 1/99 strategy will always result in less than a 100% military strategy because the filtered/funneled social production does NOT have the military bonus applied to it.  For instance, interstellar warfare, space militarization, and planetery improvements combine for a 30% military bonus.  With 50 industry on the planet funded at 100% military, this results in 65 military production.  With 50 industry on the planet funded at 1/99, this results in 49 military production (0.5 is truncated to 0, 49.5 is truncated to 49, and together they are 49).

Obviously, any point between 100/0 and 0/100 will lead to some sacrifice, but the above points are optimal because they tend to avoid the truncation as well as keep a large portion of the bonus.

Hopefully this is clear enough (clear as mud, right?)-the wiki also has some very good (and relevant) information, namely military, social, and, yes, research.

Heres a simpler explanation.

Your production values are governed by your capacity and then by funding. So if you build production structures on Colony X that give you a total capacity of 60 production and you have 25% Social, 25% Military, 50% Research and 100% production spending set in your economy screen you will see 15 military production and 15 social production so long as you are building a ship and building planetary structures. As mentioned unused social goes to military but unused military does not go to social.

25% of 60 is 15.

If you were to stop building planetary improvements but were still building a ship with the above breakdown you would see 15 social (but with arrows indicating it is being transferred to military) and 30 military production.

If you were to drop your overall production spending down to 33% while keeping the breakdown at 25% Social 25% Military and 50% Research you would see 5 social and 5 miltiary production despite having the capacity of producing up to 60. (When using both - again if you were not using your social production it would read 5 social with arrows to military and 10 military production)

If you were to set 100% overall production spending but set the breakdown to 25% Social 75% Military and 0% Research you would see 15 social and 45 military production and no research at all. Capacity produced by factories only count towards social and military production. Research capacity is governed by research buildings.

Hopefully these examples are a bit more clear.

From this you can deduce that you can never get 100% of your social/military production without completely cutting off your research. This is often the reason why your social/military production values never add up to the total of your production capacity.

You can never fully realise your full factory capacity and your full research capacity at the same time.