We describe how a common conceptual model of the application domain can be used to support a cooperative and concurrent search among loosely coupled knowledge sources distributed over a network with unknown topology. The introduction of a conceptual level, shared among all the knowledge sources in the net, allows us to obtain independence from the logical data organization of each node, not only from the physical, as is the case in distributed database management systems (DDBMS). The navigation process is based on the conceptual model and has been designed and developed by means of a set of cooperative agents, with specific knowledge and abilities, that reason about the local data and exchange information to ensure both the communication through the net and the information processing at each net node. In order to ensure the comprehension of the architecture, we include a worked-out example in the domain of pharmacology, where such a model and its associated domain-specific language have been realized.