AndreasS - You are, of course, absolutely right that “clinic” more often refers to outpatient diagnostics and treatment, but not exclusively - it can also be used for a hospital with inpatients.
They are often private hospitals, e.g. instead of waiting for an operation on the NHS, someone might opt to go into a private clinic for a few days.
“The Parkview Private Clinic is well equipped with 16 beds and modern facilities.”
“24 hour provision of excellent nursing care for medical and post-operative convalescents/respite care”http://www.parkviewclinicltdwanstead.co.uk/se...
or detox./rehab. facilities, e.g
“Betty Ford passes torch to daughter - Susan Ford Bales will take over famed clinic for substance abusers”http://www.bettyfordcenter.org/news/innews/na...
This well-known establishment is often referred to as the “Betty Ford Clinic” although its name is actually the “Betty Ford Center” – the point being that it is an example of a clinic with residential patients.
Other examples that spring to mind – the Mayo Clinic, the London Clinichttp://www.mayoclinic.com/http://www.lonclin.co.uk/
but I fully agree that one should stick to "hospital(s)" for “Klinikum”