Hello, 

Usually NCERT textbooks for 11th and 12th standard are enough for preparation for Medical entrance tests and board exams. However, if you feel like referring other books for your preparation then I have made a list of few books for physics, chemistry and biology which you can use for reference.

1. Concepts of Physics by H C Verma

2. Objective Physics by D C Pandey

3. Fundamental Physics by Pradeep

4. Physical Chemistry by OP Tandon

5. Concise Inorganic chemistry by JD Lee

6. ABC Chemistry by Modern

7. Dinesh Chemistry Guide

8. Biology vol1 and vol 2 by Trueman

9. Objective Biology by Dinesh

10. Objective Botany by Ansari

11. Pradeep Guide on Biology

You can refer any of the above mentioned books for reference.

Hope this helps.

Good Luck.