NDLTD is a searchable archive of theses and dissertations from around the world. The Global ETD Search enable Searching the electronic theses and dissertations contained in the NDLTD archive: advanced search tips how to contribute records. Advanced search tips. The archive supports advanced filtering and boolean search. Search service is a free service and is provided by the Networked Digital Library of Theses and Dissertations. The metadata is collected from universities around the world.