a type of health research conducted directly with people (patients or healthy volunteers) to evaluate the safety, effectiveness, and outcomes of drugs, medical devices, diagnostic tools, or healthcare practices. It can include activities such as asking participants questions, administering investigational treatments, taking blood or tissue samples, or monitoring patients’ progress while they receive care under a study protocol. Clinical research studies typically have defined eligibility criteria (such as age, gender, disease type, or disease stage) to determine who can be recruited or enrolled.