Perhaps you should try some spelling variations:
integration theories » integration theorems, integrationstheorie 2, integration theory
duty integration » dutch integration, data integration, why integration
import duty » import duties
11 internet » 1 internet, _ internet, im internet
support 11 » support 1, support 10, support 13
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: (( import duty integration theories. ) or ( support 11 internet service. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( import duty integration theories. ) OR ( support 11 internet service. )).
• Adding a wildcard symbol may retrieve word variants: (( import duty integration theories. ) or ( support 11 internet service. ))*.