If you mean what I think you mean, there are laptops that convert into tablets and run various versions of Windows and Linux. HP, Lenovo and so on make them, and they have all the facilities of a standard laptop plus the tablet function.
I believe that the disadvantage is that they are mainly operated by a specialised stylus rather than by a finger and they are a bit bigger than just a tablet.
Before I bought a cheap tablet, I looked at old XP ones on eBay with a view to loading a more modern OS and then the Android development system. Now I've experienced a Chinese WM8650 based tablet, I'm beginning to think that might have been a better bet.