Hello, in-service doctors are divided into certificates and double certificates. If you want to get a diploma and a degree certificate, you must take the national unified university exam. The specific time of each college is different, but it will be arranged in March and April. The choice of doctoral study depends on your personal work and family situation. Time, economy, and exams are all ok. There is no need to study on the job, but study off-job directly. On the other hand, you should also consider on-the-job study. For more details, you can also consult the admissions office of the reported school. Welcome to ask questions on 158 Education Online.