The Defense Technical Information Center (DTIC) indexes and abstracts defense-related government-sponsored scientific and technical reports. Most reports published since the late '90's are available as pdf files. The version linked below provides access to all unclassified, unlimited citations since 1975.
The DTIC R&E Gateway provides access to all citations since 1975 as described above, plus citations to documents limited to government and DoD only. In addition, a growing number of reports are provided full text. Access is limited to U.S. students, faculty and staff, and requires an individual password and/or registered CAC login.
Government and other agencies produce defense-related reports that are relevant to research in Operations Research and related curricula. The following list of agencies producing defense-related reports is not comprehensive.