AIIMS Questions paper are not available online. You may try to use AIIMS Explorer from MTG or other publishers like Arihant. However their accuracy cannot be verified.The recent question papers that from 2014 to 2018 are all based on the students memory that he/she could recall.These papers can be found in modules of coaching centres where they gather info and questions from its students.

hi shahid rahmani, you can get the previous years question papers from the market or online from publishers like arihant or mtg, they would also provide you with answers and detailed explanation, i suggest you practise all in a timed manner , analyse and rectify your mistakes.good luck