I use Kindle Touch eReader and I've installed latest Calibre on my PC.

Want to convert Harrison's Principles of Internal Medicine, 18th Edition around 400 mb in .chm format and when I convert them to .mobi it results in 1.3 mb or 300 kb in .mobi format. When I read them on my reader it shows only the first 20-30 pages instead of 8000. I can see the Table of Contents. Can someone explain why is this happening please? And if there is somewhat a solution?