Perhaps you should try some spelling variations:
"city cooperation theories" » "city cooperation series", "city cooperation theory", "city collaboration theories", "city corporation theories", "china cooperation theories", "city corporations theories"
"its colonization israel" » "its communication israel", "its colonization still", "its colonization history", "anti colonization israel", "jews colonization israel", "mrsa colonization israel"
"mars colonization failed" » "mars colonization still", "mars organizations failed", "mrsa colonization failed", "jews colonization failed", "pro colonization failed"

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: (("its colonization israel") or ((("mars colonization failed") or ("city cooperation theories"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("its colonization israel") OR ((("mars colonization failed") OR ("city cooperation theories")))).
• Removing quotes may allow a broader search: (( its colonization israel ) or ((( mars colonization failed ) or ( city cooperation theories )))).
• Adding a wildcard symbol may retrieve word variants: (("its colonization israel") or ((("mars colonization failed") or ("city cooperation theories"))))*.