1. Kerlinger (1986): "Systematic, controlled, empirical and critical investigation of hypothetical propositions about the presumed relations among natural phenomena."
2. Best & Kahn (1986): "Formal, systematic and rigorous process of inquiry aimed at discovering and interpreting facts, revising accepted theories, or developing new theories."
3. Ary, Jacobs & Razavieh (2002): "A systematic investigation into a problem or question, undertaken to increase our understanding of the problem or to develop a solution."
4. Creswell (2014): "A process of gathering and analyzing information for the purpose of describing, explaining, predicting, or controlling phenomena."
5. Leedy & Ormrod (2013): "A systematic attempt to find answers to questions."
6. Fraenkel & Wallen (2006): "A systematic process of collecting and analyzing information to increase our understanding of the world around us."
7. Babbie (2013): "A systematic inquiry whose objective is to describe, predict, or control phenomena."
8. Cook & Campbell (1979): "A process of systematically and rigorously investigating a problem or question in order to increase our knowledge about it."
9. Punch (2005): "A formal, systematic and rigorous process of inquiry that aims to discover and interpret facts and to revise accepted theories."
10. Tuckman (1978): "A systematic and controlled inquiry or investigation into a specific problem or question in order to discover new facts or to establish or refute a hypothesis."
Key themes that emerge from these definitions:
* Systematic: Research follows a structured, organized plan.
* Controlled: Research attempts to minimize bias and influence.
* Empirical: Research relies on evidence and data.
* Critical: Research involves careful analysis and evaluation.
* Inquiry: Research is a process of investigation and exploration.
* Knowledge: Research aims to expand understanding and knowledge.
* Problem-solving: Research may seek solutions to specific issues.
Note: These definitions provide a general overview of what research is. The specific definition of research can vary depending on the context, the type of research being conducted, and the field of study.