Perhaps you should try some spelling variations:
"mars colonization failed" » "mars colonization still", "mars organizations failed", "mrsa colonization failed", "its colonization failed", "jews colonization failed"
"city cooperation sources" » "city cooperation series", "city cooperation studies", "city cooperation countries", "city corporation sources", "china cooperation sources", "city corporations sources"
"jews communication iran" » "nets communication iran", "lea's communication iran", "mass communication iran", "jews communication iraq", "jews communication ireland", "jews communication brands"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("jews communication iran") or ((("mars colonization failed") or ("city cooperation sources"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("jews communication iran") OR ((("mars colonization failed") OR ("city cooperation sources")))).
• Removing quotes may allow a broader search: (( jews communication iran ) or ((( mars colonization failed ) or ( city cooperation sources )))).
• Adding a wildcard symbol may retrieve word variants: (("jews communication iran") or ((("mars colonization failed") or ("city cooperation sources"))))*.