Many technical reports are available free from:
(1) the issuing organization's website;
(2) the U.S. Government Printing Office's website http://www.gpo.gov/fdsys;
(3) the federal government Internet portal USA.gov;
(4) a web search on Google http://www.google.com.
(5) departmental web pages for top ranking schools you know have strong programs in the subject area of interest (see below)