What are Technical Reports?
The detailed publications that record results of scientific studies. Department of Energy (DOE) and National Aeronautics and Space Administration (NASA) are the federal agencies that produce a large number of technical reports.(http://www.lib.cwu.edu/GovernmentDocumentsGlossary) Often times these reports are published electronically and therefore are relatively easy to access with the write gateway.
For more information on Technical Reports and the relationship with Grey Literature check out GLISC's Guidelines for the production of scientific and technical reports: how to write and distribute grey literature.(http://www.glisc.info/)
Are you using the The National Technical Information Service (NTIS) to search for technical reports? This guide mmay be useful in helping yopu to maximize your searches. www.ntis.gov/pdf/dbguid.pdf