Perhaps you should try some spelling variations:
"clean development series." » "clean development services.", "clean development agencies.", "clean development africa.", "urban development series.", "child development series."
"human development series." » "human development services.", "human development agencies.", "human development africa."
"a development policy." » "_ development policy.", "asian development policy.", "city development policy."

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

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