On or eBay , you can find used copies of GK Pal (2nd edition) for as little as ₹300 ($4 USD). Physiology doesn't change that much in 5 years. A cheap hard copy is better than a buggy PDF.
The biggest strength of G.K. Pal’s physiology is that it is written specifically with the Indian medical curriculum and competitive exams in mind. Unlike standard international texts (like Guyton or Ganong), which are narrative and vast, G.K. Pal is concise and bulleted. It is widely considered the "Bible" for Physiology for NEET PG preparation. gk pal physiology pdf google drive free