There is a need for specialized search engines focused on specific disciplines that can use domain knowledge to guide the user to find exactly the resources they are searching for. In addition, these engines should be able search multiple and heterogeneous resource catalogs simultaneously and aggregate results from these catalogs. Noesis, a customizable search engine with semantic and resource aggregation capabilities is presented in this paper. The Noesis architecture has been designed to be modular, allowing it to be adapted by projects in different disciplines. This paper describes the Noesis architecture, highlights its application in several projects, and presents a user scenario for one of the projects is presented in this paper.