But some people are new to research community, don't know about the other research platform where they can easily get required articles without requesting to other people on research gate.
I find it odd that people know about Research Gate (which has very incomplete coverage) and not about Google Scholar (which has everything). Google scholar is so useful it should be the first thing that is taught to any student.
Another tip is to search for "Name Publications". Most scholars have their full texts on their web site. They don;t see much point in posting it to Research Gate as well.
Trevor Bench-Capon Yes, that's the miserable situation. Anyway, I am absolutely agree with you. Google Scholar is much more useful and easy to access when compared to research Gate.