Perhaps you should try some spelling variations:
"c's communication issues" » "c's community issues", "c's communication india", "c's communication united", "lea's communication issues", "class communication issues", "mass communication issues"
"mars colonization still" » "mars colonization failed", "mars colonization israel", "mars colonization songs", "mrsa colonization still", "its colonization still", "jews colonization still"
"city cooperation state" » "city cooperation scale", "city operation state", "city cooperation strategy", "city corporation state", "china cooperation state", "city corporations state"

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: (("c's communication issues") or ((("mars colonization still") or ("city cooperation state"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("c's communication issues") OR ((("mars colonization still") OR ("city cooperation state")))).
• Removing quotes may allow a broader search: (( c's communication issues ) or ((( mars colonization still ) or ( city cooperation state )))).
• Adding a wildcard symbol may retrieve word variants: (("c's communication issues") or ((("mars colonization still") or ("city cooperation state"))))*.