double-blind
adjective science, medical specialized uk/ˌdʌb.əlˈblaɪnd/ us/ˌdʌb.əlˈblaɪnd/
（尤指药物）双盲测试的（受试者和医生均不知道哪一组在接受测试）
A double-blind study or trial, especially in medicine, is one in which two groups of people are studied, for example with one group taking a new drug and one group taking something else, but neither the people in the study nor the scientist or doctor knows which person is in which group.