Perhaps you should try some spelling variations:
"structural considerations" » "cultural considerations", "statistical considerations", "structural constraints"
"structural conditions" » "structural transitions", "structural control", "natural conditions"
"structure functions" » "structure function"

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: (((("structural conditions") OR ("structural considerations"))) OR ("structure functions"))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"structural conditions\") OR (\"structural considerations\"))) or (\"structure functions\"))*".
• Removing quotes may allow a broader search: (((( structural conditions ) OR ( structural considerations ))) or ( structure functions ))*.