NEST

The official link is https://cdn3.digialm.com//EForms/configuredHtml/1834/54475/login.html
But currently it is in maintenance so you can check on 28 August 2018. Hope your doubt will resolve.
Best of luck.

In NEST, questions from all the three Physics Chemistry and Maths will be asked.

Hello,
Yes, you can apply for NEST with biology subject.

Hi, It's not possible. You have to do a basic degree or graduation in any subject you like and then you can apply for M.Sc.

Get all the required information from below link:
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/college/national-institute-of-science-education-and-research/exams/amp/nest&ved=2ahUKEwi9y-TBmqPcAhWMQo8KHUzyC_gQFjABegQIBBAB&usg=AOvVaw3EOMaoKBbE43DwlUoRg59N&cf=1.

Books for different subjects are -
PHYSICS:
Aptitude Test Problems in Physics by S. S Krotov
Concepts of Physics by H. C. Verma
NEET - 2012 Physics Objective Question bank Chapter wise and Topic Wise by Digvijay Singh
Physics for Engineering and Medical Entrance Examinations by Ajit Singh Panwar
Problems

Kindly refer to the link below:
https://www.shiksha.com/college/national-institute-of-science-education-and-research/exams/nest/cutoff

Mentioned below are the top 5 coaching centers for NEST in Odisha:
1. Achivia
2. Odisha Institute
3. Mindmasters
4. Career Launcher Patia
5. Ims Nayapalli.