The following list of websites include some full text of many documents for downloading or printing

Defense Technical Information Center (DTIC) Technical Reports Collection
http://stinet.dtic.mil/str/tr_fields.html
This site has a searchable database of unrestricted DoD technical reports from 1975 to present. Documents added since September 1998 are available in full text. DoD is the world's largest producer of technical reports.

Department of Energy Technical Standards
http://tis.eh.doe.gov/techstds/
This site contains approved and draft DOE technical standards.

DigiDoc System (Maintained by the NASA UniLibrary)
http://digidoc.larc.nasa.gov/
This contains some full-text, scanned reports from Ames, Dryden, Langley and Lewis. Some NACA reports are also included.

DOE Information Bridge
http://www.osti.gov/bridge/
This site provides access to over 2 million full-text pages, courtesy of the Department of Energy and Government Printing Office. It includes, but is not limited to, subjects in the areas of physics, chemistry, materials, biology, environmental sciences, energy technologies, engineering, computer and information science and renewable energy.

Johnson Space Center's Document Index System (DIS)
http://jsc-isd-lib14.jsc.nasa.gov/dis/
Although primarily an index, this site does includes some links to full text documents.

NASA Documents Online
http://www.hq.nasa.gov/office/hqlibrary/books/nasadoc.htm
This site, brought to you courtesy of NASA Headquarters Library, provides links to over 175 full-text NASA documents.

NASA/ KSC Technical Documentation System
http://tdsearch.ksc.nasa.gov

NASA Tech Briefs Online
http://www.nasatech.com/TSP/body.html
After registering online, one may download Technical Support Packages (TSPs) which facilitate the transfer and communication of NASA technology.

NASA Technical Standards
http://standards.nasa.gov/
A comprehensive source for standards of all types.

National Advisory Committee for Aeronautics
http://naca.larc.nasa.gov/
NACA is the precursor the NASA, and this site contains some full text NACA documents from 1921-1958.

National Science Foundation Documents Online
http://www.nsf.gov/cgi-bin/pubsys/browser/odbrowse.pl
This allows access to some NSF forms, policies and procedures and reports.

NIST Chemistry WebBook
http://webbook.nist.gov/chemistry/
This database contains IR spectra for over 5000 compounds, mass spectra for over 10,000 compounds as well as ion energetics data for over 14,000 compounds. It may become fee-based in the future.

NODIS-NASA Online Directives Information System
http://nodis3.gsfc.nasa.gov/
NASA directives (NPDs, NPGs, etc.) and links to Centers directives databases can be found here.

Space Shuttle Program Documents
http://www.unitedspacealliance.com/icd/
This site includes CORE/IDD, ICD, IRD and GSE ICD documents.

United States Geological Survey Open-File reports (Online)
http://geology.usgs.gov/open-file/
Although not a comprehensive list, this site contains unpublished manuscript reports, maps, and other material that are made available for public consultation at depositories dating mainly from 1990 on. A few older items are also available.