Each paper that you find will have an associated ID number. Go to the govt. A librarian can point you to a card catalog that lists all of the documents they have. Look up the ID number of each paper in the card catalog to see if it is in stock. If it is, you can fill out a card and give that to another librarian, who will fetch the microfiche that hold your paper.
Technical reports tend to be hell to find.
They're not published, so libraries rarely carry them. Natalie Sipes is the person to ask in this Department for help in locating tech reports. Many of them are in the 2nd floor reading room. Some are available on-line. There's also a company called Research Access, Inc. that distributes some technical reports.