Perhaps you should try some spelling variations:
"world bank regional and sectional studies" » "world bank regional and functional studies", "world bank regional and regional studies", "world bank regional and sectional study", "world lanka regional and sectional studies", "world park regional and sectional studies", "world urbano regional and sectional studies"
"world bank regional and doctoral studies" » "world bank regional and doctoral students", "world bank regional and doctoral student", "world bank regional and cultural studies", "world lanka regional and doctoral studies", "world park regional and doctoral studies", "world urbano regional and doctoral studies"
"world bank regional and spectral studies" » "world bank regional and structural studies", "world bank regional and general studies", "world lanka regional and spectral studies", "world park regional and spectral studies", "world urbano regional and spectral studies"
"world mask regional and spectral studies" » "world mask regional and structural studies", "world mask regional and general studies", "world mask region and spectral studies", "world park regional and spectral studies", "world risk regional and spectral studies", "world mark regional and spectral studies", "world mass regional and spectral studies", "world task regional and spectral studies"

Try widening your search to All Fields.

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 doctoral studies") OR ((("world bank regional and spectral studies") OR ("world mask regional and spectral studies"))))) OR ("world bank regional and sectional studies")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"world bank regional and doctoral studies\") or (((\"world bank regional and spectral studies\") OR (\"world mask regional and spectral studies\"))))) or (\"world bank regional and sectional studies\"))".
• Removing quotes may allow a broader search: (((( world bank regional and doctoral studies ) or ((( world bank regional and spectral studies ) OR ( world mask regional and spectral studies ))))) or ( world bank regional and sectional studies )).
• Adding a wildcard symbol may retrieve word variants: (((("world bank regional and doctoral studies") or ((("world bank regional and spectral studies") OR ("world mask regional and spectral studies"))))) or ("world bank regional and sectional studies"))*.