It is common for all games in series to control money/research/luxury... In this game I can't find how to control taxes spending. It is unavailable now?
You can't increase money to science.
At least not directly.
Unlike Civilization 4, there is no economy that gets split into gold/science/culture/espionage. Instead, science is created directly as science.
The best you can do is switch your citizens to working as scientist specialists, or on tiles that produce science. (Academies built by a Great Scientist) The easiest way to do this is by setting a city's focus to science, but if you specifically are making more gold than you need, you can take individual citizens off gold rich tiles and lock them in to working on academies or (I think) as specialists.
Finally, you can set cities to "build" science like you could in Civilization 4. It requires a specific technology again. (Which I don't remember)
The method you want isn't in Civilization 5, but hopefully you can get close to what you wanted with these alternatives.