Hi pal,

It's good choice to go for integrated course, specialization  in particular subject will be selected by you after completion of b. Sc dgree. there are some universities which provides education in integrated courses.

1. National Institute of Science educational research- through nest entrance.

2.IISC -trough KVPY /jee entrance .

3.iiser-trough iiser entrance.

Hope this will help you.
Good luck.