I use Matlab on my MacBook Pro with Retina display.
Using get(0,'ScreenSize'), we obtain
ans =
1 1 1440 900
instead of 1 1 2880 1800. Is there any way to work with right sizes?
No, 1440-by-900 is likely the correct effective value for your screen's resolution. This is the value that the OS tells applications and is not the the same as the number of pixels (sometimes referred to as the "native resolution"). However, applications also need to check if a display supports HiDPI mode (a.k.a. Retina) as well. In your case, each "retina pixel" is made up of a 2-by-2 set of raw pixels (which, in turn, each have RGB sub-pixels). Applications that are "Retina-aware" can then render certain graphics (e.g., images and video) at the the full native resolution within regions of the screen. Some more details – probably more accurately stated – can be found in this article.
There are 3rd-party solutions to run OS X at the native resolution (e.g., SwitchResX and the methods discussed here), but this of course makes everything, UI included, ridiculously tiny. If you're running one of these, Matlab should report your resolution as 2880-by-1800.
I am not aware of any Matlab options, properties, or functions that allow one to actually take advantage of advantage of a Retina display. This means that, for example, when you display an image, each of it's pixels are rendered as 2-by-2 retina pixels.