Danshi vs keshi

Long time ago I was learning a couple of words in Chinese, and I still remember "danshi" as for "but", but... here we learn keshi. What's the difference?

This may be more than you are looking for... but google search "Textual and contextual contrast connection: A study of Chinese ..." and you should find the article I only read the abstract and I felt I gained a lot just from that. Prior to this I had just been using whichever danshi or keshi I felt flowed better in the sentence. I am a college student and I might be signed into the library and that is how I have access on science direct.com but I think you should be able to get into it.

O, great article! Xie xie!