There are only 3 entrances for MBBS and these are - NEET, AIIMS and JIPMER and till now only JIPMER is not out as rest have started their registration.

Please check below details -

NEET 

Important Dates -

NEET 2018 Application Form available - February 8, 2018

Last date for submitting NEET Application Form - March 9, 2018 (upto 11:50 PM)

https://medicine.careers360.com/articles/neet-important-dates

Exam Pattern -

Mode of Examination - Offline (Pen and Paper)

Duration of Examination - 3 hours

Medium of Exam - English, Hindi, Assamese, Bengali, Gujarati, Marathi, Tamil, Telugu, Oriya, Kannada and Urdu

Type of Questions - Multiple Choice Questions

Sections - 

• Physics – 45 Questions

• Chemistry – 45 Questions

• Biology – 90 Questions

Total Number of Questions - 180 Questions

Total Marks of Examination - 720 Marks

Marking Scheme - For each correct answer, the candidates will be awarded 4 marks; if an answer is wrong, then 1 mark will be deducted.

https://medicine.careers360.com/articles/neet-exam-pattern

AIIMS -

Important Dates -

AIIMS MBBS Application Process opens - February 5, 2018

Application Process closes - March 5, 2018 (5.00 PM)

https://medicine.careers360.com/articles/aiims-mbbs-important-dates

Exam Pattern -

Exam Mode Computer Based Test (CBT) – Online

AIIMS MBBS Number of Sessions Two Sessions - Morning and Afternoon

Type of Examination - Objective type

Language of Paper - English and Hindi options

Total Questions - 200

Question Type - Multiple-choice, reason-assertion based

https://medicine.careers360.com/articles/aiims-mbbs-exam-pattern

JIPMER

Important Dates -

Online registration begins - March 7, 2018 (Wednesday)

Last date to apply or register for JIPMER MBBS 2018 - April 13, 2018 (Friday)

https://medicine.careers360.com/articles/jipmer-mbbs-important-dates

Exam Pattern-

Mode of JIPMER MBBS Exam - Online, Computer Based Exam (CBT)

Language of JIPMER MBBS Question Paper English

Total Number of Questions - 200

Type of Questions - MCQ (Multiple Choice Questions)

Marking Scheme +4 for Correct Response. NO Negative Marking.

https://medicine.careers360.com/articles/jipmer-mbbs-exam-pattern

Good Luck!!!