After completing 12th Science, there are several courses you can pursue based on your interests and career goals. Here’s a detailed overview of some popular options:

1. **Engineering**:
**B.Tech/B.E.**: You can specialize in various fields like Computer Science, Mechanical, Civil, Electrical, etc. Admission is typically through entrance exams like JEE Main, JEE Advanced, or state-level exams.

2. **Medical Sciences**:
**MBBS**: If you're interested in becoming a doctor, you can pursue a Bachelor of Medicine and Bachelor of Surgery. Admission is through NEET.
**BDS**: Bachelor of Dental Surgery is another option if you're interested in dentistry.
**Nursing**: B.Sc. in Nursing is a good choice for those looking to enter the healthcare sector.

3. **Pure Sciences**:
**B.Sc.**: You can pursue a Bachelor of Science in subjects like Physics, Chemistry, Biology, Mathematics, or Environmental Science. This is a good foundation for research or further studies.

4. **Pharmacy**:
**B.Pharm**: A Bachelor’s in Pharmacy can lead to a career in pharmaceuticals, research, or healthcare.

5. **Information Technology**:
**BCA**: A Bachelor in Computer Applications is suitable for those interested in IT and software development.

6. **Design**:
**B.Des**: If you have a creative inclination, courses in design (like Fashion Design, Interior Design, Graphic Design) can be pursued.

7. **Agriculture**:
**B.Sc. in Agriculture**: This is a good option for those interested in agricultural sciences and farming technology.

8. **Other Professional Courses**:
**Hotel Management**: A degree in hospitality can lead to careers in the hotel and tourism industry.
**Airline and Airport Management**: This field offers opportunities in the aviation sector.

9. **Management**:
**BBA**: A Bachelor of Business Administration can be pursued for a career in business and management.

10. **Law**:
**5-Year Integrated LLB**: If you're interested in law, you can pursue an integrated law course after 12th.

Each of these paths has its own set of entrance exams and eligibility criteria, so it's important to research thoroughly based on what interests you the most. Let me know if you want more information on any specific course!