Perhaps you should try some spelling variations:
international efforts » international airports, international energy, international airport
interaction series » interactions series, interaction studies, interaction terms
den international » den internationalen, when international, can international
can interaction » can integration, ijn interaction, cavern interaction
supply den » supply ann, supply demand, supply design
supply can » supply chain, supply case, supply chai

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply den international efforts. ) or ( supply can interaction series. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply den international efforts. ) OR ( supply can interaction series. )).
• Adding a wildcard symbol may retrieve word variants: (( supply den international efforts. ) or ( supply can interaction series. ))*.