Perhaps you should try some spelling variations:
integration theory » integration through, information theory, innovation theory
gain internet » im internet, das internet, good internet
mail internet » many internet, mit internet, mobile internet
a integration » 3 integration, 2 integration, 4 integration
support a » support _
service. » services.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply ((gain internet) OR (mail internet)) service. ) or ( support a integration theory. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply ((gain internet) OR (mail internet)) service. ) OR ( support a integration theory. ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( supply ((gain internet) OR (mail internet)) service. ) or ( support a integration theory. ))*".