Perhaps you should try some spelling variations:
"de communication issues" » "de community issues", "de communication india", "de communication united", "mobile communication issues", "online communication issues"
"early cooperative studies" » "early comparative studies", "early cooperation studies", "early cooperative strategies", "early postoperative studies", "dairy cooperative studies"
"its colonization israel" » "its communication israel", "its colonization still", "its colonization history", "anti colonization israel", "jews colonization israel", "mars colonization israel"

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"de communication issues\") OR (((\"early cooperative studies\") OR (\"its colonization israel\"))))~".
• Removing quotes may allow a broader search: (( de communication issues ) OR ((( early cooperative studies ) OR ( its colonization israel ))))~.
• Adding a wildcard symbol may retrieve word variants: (("de communication issues") OR ((("early cooperative studies") OR ("its colonization israel"))))*.