I've emailed over thirty five potential supervisors and did not receive any positive response. Should I keep emailing?
Professors are quite limited with funds and resources (or already have a full team). The likelihood that someone who emails out of the blue to be a suitable choice is slim. Some places probably need a commitee to hire, as a safeguard against discrimination and errors.

You are far better off looking for universities with open positions, I think, or strengthen the connections with professors who already know you (and might write a recommendation letter for you). 

Also, publications are way better than grades, research experience is very valuable (at least in maths, I suspect other fields are similar).