Perhaps you should try some spelling variations:
"descriptions system" » "descriptor systems"
"descriptive phase" » "descriptive plates", "descriptions phase", "descriptive clause"
"descriptive case" » "descriptive clause", "descriptive based", "description case"

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: (((("descriptive phase") OR ("descriptive case"))) OR ("descriptions system")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"descriptive phase\") OR (\"descriptive case\"))) or (\"descriptions system\"))".
• Removing quotes may allow a broader search: (((( descriptive phase ) OR ( descriptive case ))) or ( descriptions system )).
• Adding a wildcard symbol may retrieve word variants: (((("descriptive phase") OR ("descriptive case"))) or ("descriptions system"))*.