 Institute ("instituto") and school ("escola") are also common designations for autonomous units of Portuguese higher learning institutions, and are always used in the polytechnical system, though several universities also use these systems.Access to public higher education institutions is subject to enrollment restrictions (numerus clausus), and students must compete for admission.Students who hold a diploma of secondary education (12th grade) or the equivalent, who meet all legal requirements, particularly exams in specific subjects in which minimum marks must be obtained, may apply.