Perhaps you should try some spelling variations:
sectional studies » functional studies, regional studies, sectional study
doctoral studies » doctoral students, doctoral student, cultural studies
planes regional » lakes regional, pages regional, panels regional
lanea regional » lanka regional, area regional, iaea regional
bank regional » lanka regional, mask regional, park regional

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