Perhaps you should try some spelling variations:
"clean development studies." » "clean development services.", "clean development strategies.", "clean development strategy.", "human development studies.", "urban development studies."
"a development series." » "a development services.", "a development agencies.", "a development strategies."
"_ development series." » "_ development services.", "_ development agencies.", "_ development strategies."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("a development series.") OR ("_ development series."))) or ("clean development studies."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("a development series.") OR ("_ development series."))) OR ("clean development studies."))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"a development series.\") OR (\"_ development series.\"))) or (\"clean development studies.\"))*".
• Removing quotes may allow a broader search: (((( a development series. ) OR ( _ development series. ))) or ( clean development studies. ))*.