1, medicine
There is no doubt that the medical profession ranks first. The medical education system is very long. Basically, the undergraduate course is five years, and it is not easy to find a job after graduation. The minimum requirement of a top-three hospital is a master's degree, so you need to consider studying for a doctor's degree, otherwise you will not win the trust of patients. There is still a lot of knowledge to learn, and it will take a lifetime to learn, not only from textbooks, but also from practice. It is not a problem to be a mouse. Studying medicine is a word, never too old to learn.
2. Law
Don't mention how difficult it is to study law. Reciting is a common practice. Let's say that a book as thick as the Civil Code requires a lot of brain power to read thoroughly. Not only that, the requirements of legal logical thinking are not low.
3. Mathematics
Mathematics requires people's logical thinking very highly. I believe everyone should go to college and rack their brains for advanced mathematics. What's more, the mathematics mentioned here is not high school mathematics or advanced mathematics, but a collection of all mathematics. Mathematical analysis, analytic geometry, advanced algebra and ordinary differential equations don't bother you. Learning real variable function and functional analysis is very difficult, especially difficult and painful!
4. Neuroscience
Its research is a branch of biology, and its contents are all obscure knowledge. There are not many universities offering this major in China, but they are all powerful universities. Neuroscience is an interdisciplinary subject. Learning this science requires a deep understanding of other fields. Students majoring in this major, you should study yourself well then.
Quantum mechanics: because many students can't understand this course, the teacher can't speak too carefully, so he can only recite it from the book. To understand this course, students still need to spend a lot of energy after class. If you want to fail, you can only work hard silently.