General:
* Research
* Learning
* Education
* Academic pursuits
* Scholarly work
* Investigations
* Inquiries
* Explorations
Specific to a particular field:
* Dissertations (for doctoral studies)
* Theses (for master's studies)
* Experiments (for scientific studies)
* Analyses (for data-driven studies)
* Surveys (for sociological studies)
Informal:
* Schoolwork
* Books
* Lessons
* Reading
Figurative:
* Pursuit of knowledge
* Quest for understanding
Please provide more context so I can offer a more precise suggestion. For example, are you talking about academic studies, scientific studies, or something else?