wa alaykom assalam
takleef has an arabic meaning which is a public service the doctor should do for about 2 years as a general practitioner in health centers(not highly equipped) just after finishing the medical study then the doctor can start his residency.
doctors who will be hired in faculties and those who will spend their military service don't have to do their (takleef).
so literally (takleef) means in english duty or imposition
i hope that this is what you asked for