Production of each type is dependent on both the base production of each unit, along with the % used on your economy slider. EG, your capital city give 12 research pts and 12 mil/soc pts, but only if your slider is set to 100%. If your slider is set to 50%, then you get 6 pts of each (base). This is then divided further by your your allocation of mil, soc, and research in the Domestic Policy Screen. If you divide your points 3 ways (33% each) you only get 2 to 3 points of each type.

This then is used to determine what you get when you "focus". If you have 33% each and you focus social, then 50% each of your military and research will be diverted to social, but at a 50% penalty. This means you will get about 1 to 2 points extra social construction.

This is also true of research, but the formula works a little worse. If you build a colony that is all factories (the all-x approach), you focus some of your construction into research at the same 50% of 50% formula. A basic factory provides 8 points of construction. If focused to research, this gives 2 points of research. That's it, a measly 2 pts. At that rate, it would take you a couple of game years to research almost any worthwhile tech.
That being said, most serious high level players use this strategy. They just build tons of factories and accept that they are going to suck at research till they can militarily bully the AI into trading them all the good techs.

Another thing is that social and military projects are built per-planet, so when you change focus you can see the changes to the build time. Since research is civilization wide, changing the focus on one planet, or even a couple, may not give enough additional Research Points to change the time it will take to complete a new tech.

This can also happen with social and militry projects. The change in the numbers at the top of the screen next to the shields , hammers and beekers will change more on planets with a greatr mix of labs and factories.

So the "all factories" method doesn't work if you play with tech trading disabled?

All-factories works with tech trade off. Being a bully to the AI is just one method of getting techs you want. Another is called invading planets. You'll steal the techs with your mighty military production of slightly substandard units when you capture the enemy's planets.

At the top of the planet's colony management screen, it shows the military, social, and research production.  On the right side of each section is a button that looks like 3 small concentric circles with an arrow head pointing down from the top of them.  Click on that to focus production.

Another way is in the civilization manager.  The colonies tab shows you a spreadsheet like view of all of your colonies.  For each, it shows the military, social, and research production.  Click on one of those for a planet and it will turn on the focus, and it will be highlighted.  Click on it again to turn it off.