Perhaps you should try some spelling variations:
integration theories » integration theorems, integrationstheorie 2, integration theory
internet services » internet service
duty integration » dutch integration, data integration, why integration
import duty » import duties
support 11 » support 1, support 10, support 15
support 13 » support 1.3, support 3, support 1

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( import duty integration theories. ) or ( ((support 11) OR (support 13)) internet services. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( import duty integration theories. ) OR ( ((support 11) OR (support 13)) internet services. )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( import duty integration theories. ) or ( ((support 11) OR (support 13)) internet services. ))".
• Adding a wildcard symbol may retrieve word variants: (( import duty integration theories. ) or ( ((support 11) OR (support 13)) internet services. ))*.