You are looking for exam papers for PG exams with solutions. For solutions, it is easier to buy books online.
A. JIPMER PG entrance exam papers
(https://www.entrancecorner.com/medical/jipmer-pg-previous-year-question-papers/)
(https://www.freshersnow.com/jipmer-pg-previous-papers/#JIPMER_PG_Entrance_Exam_Model_Papers)
(https://www.mygpscexam.com/2015/03/jipmer-previous-years-question-paper-pdf.html)
You want JIPMER PG papers with explanations. You can try Target Jipmer Pgmee set Paperback – 2017
by Arun Babu (Author). This has questions and the answeres with explanations.
B. FOR AIIMS
You need to register in this site to get 5 years PG entrance exam papers (https://www.educationobserver.com/forum/showthread.php?tid=17508).
This is the link for PDF AIIMS 2016 PG paper(https://drive.google.com/file/d/1l7Qu6J0TXsgF_s2ltMGaI1rzbotNYbM5/view). Some papers from 2001 to 2017 can be checked on this site (https://www.examtime.co/aiims-pg-question-paper/).
This site (https://www.aim4aiims.in/pg/download.php) has many free downloads. we get PDF files like this one from 2010 (https://www.aim4aiims.in/download/9159faca9ed9233.pdf).
C. DNB CET old PG questions papers
This site (http://www.oldquestionpapers.net/dnb-cet-question-paper-answer-previous-year-old-papers) has some subject wise that you can browse.
This site needs a registration (https://www.jbigdeal.in/dnb-cet/#DNB_CET_Previous_Year_Question_Papers) for old papers.
D. NEET PG question papers and practice papers can be downloaded from here.
(https://www.examrace.com/NEET-PG/NEET-PG-Practice-Tests/)
E. Some books with explanations can be found in
1.Review of PGI Chandigarh Paperback – 2018 by Mukhmohit Singh (Author), Shveta Saini (Author)
2.PGI Chandigarh – (Volume - 1: 2016-2012) (Postgraduate Medical Entrance Exam) (SEVENTH EDITION) by Manoj Chaudhary
3. AIIMS PGMEE November 2017 Perfect Paperback – 2017 by Dr. Sandhya Gaur Dr. Apoorv singh (Author).
4. AIIMS PGMEE SOLUTIONS VOL-1A VOL-1B (2016-2013) Paperback – 2017
by Amit Tripathi Ashish Gupta (Author)
5. Self Assessment & Review of DNB-PDCET, DNB-CET, JULY 2013 : for DNB-PDCET, DNB-CET AIPGMEE (New Pattern), AIIMS and Regional PGMEEs (DNB - PDCET AND DNB - CET) Paperback – 2013
by Alok Aggarwal (AA) (Author), D. K. Taneja (Foreword)
6. A Complete Guide To Dnb–Cet (2011 – 2000): Fully Explanatory With References From Latest Edition Of Standard Textbooks Paperback – 2013
