Perhaps you should try some spelling variations:
"world bank regional and sectoral studies" » "world bank regional and sectional studies", "world bank regional and sector studies", "world bank regional and doctoral studies", "world lanka regional and sectoral studies", "world urbano regional and sectoral studies", "world urban regional and sectoral studies"
"world mask regional and spectral studies" » "world mask regional and structural studies", "world mask regional and sectional studies", "world mask regional and general studies", "world mask region and spectral studies", "world risk regional and spectral studies", "world masons regional and spectral studies", "world mark regional and spectral studies", "world task regional and spectral studies", "world map regional and spectral studies"
"world park regional and spectral studies" » "world park regional and structural studies", "world park regional and sectional studies", "world park regional and general studies", "world parks regional and spectral studies", "world part regional and spectral studies", "world park region and spectral studies", "world par regional and spectral studies", "world pork regional and spectral studies"
"world mass regional and spectral studies" » "world mass regional and structural studies", "world mass regional and sectional studies", "world mass regional and general studies", "world masons regional and spectral studies", "world massif regional and spectral studies", "world cases regional and spectral studies", "world maps regional and spectral studies", "world map regional and spectral studies", "world may regional and spectral studies"
"world bank regional and sectional study" » "world lanka regional and sectional study", "world urbano regional and sectional study", "world urban regional and sectional study"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("world bank regional and sectoral studies") OR ((((("world mask regional and spectral studies") OR ("world park regional and spectral studies"))) OR ("world mass regional and spectral studies"))))) OR ("world bank regional and sectional study"))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"world bank regional and sectoral studies\") or (((((\"world mask regional and spectral studies\") OR (\"world park regional and spectral studies\"))) or (\"world mass regional and spectral studies\"))))) or (\"world bank regional and sectional study\"))*".
• Removing quotes may allow a broader search: (((( world bank regional and sectoral studies ) or ((((( world mask regional and spectral studies ) OR ( world park regional and spectral studies ))) or ( world mass regional and spectral studies ))))) or ( world bank regional and sectional study ))*.