Perhaps you should try some spelling variations:
"road corporation" » "said corporation", "_ corporation"
"railroad corporation" » "railsaid corporation", "rail_ corporation", "railroads corporation"
"a corporation" » "_ corporation", "a corporate"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("road corporation") OR ("railroad corporation"))) OR ("a corporation")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"road corporation\") OR (\"railroad corporation\"))) or (\"a corporation\"))".
• Removing quotes may allow a broader search: (((( road corporation ) OR ( railroad corporation ))) or ( a corporation )).
• Adding a wildcard symbol may retrieve word variants: (((("road corporation") OR ("railroad corporation"))) or ("a corporation"))*.