Not directly in the UI. Services may disappear or and appear again when there are no requests. At the moment I don't think there is other option than to use the API a continuously compare the services seen with the services that have been detected previously.
Maybe a first seen and last seen metadata for a service in Dynatrace would be a nice RFE.
Certified Dynatrace Master | Alanata a.s., Slovakia, Dynatrace Master Partner
