Perhaps you should try some spelling variations:
"a marked decrease" » "a marked increase" (Expand Search), "_ marked decrease" (Expand Search), "a marker decrease" (Expand Search), "a market decrease" (Expand Search)
"a large decrease" » "a larger decrease" (Expand Search), "a large increases" (Expand Search), "a large degree" (Expand Search), "_ large decrease" (Expand Search)
"b large decrease" » "b larger decrease" (Expand Search), "b large increases" (Expand Search), "b large degree" (Expand Search), "_ large decrease" (Expand Search), "_ larger decrease" (Expand Search)

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("a large decrease") OR ("a marked decrease"))) OR ("b large decrease"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"a large decrease\") OR (\"a marked decrease\"))) OR (\"b large decrease\"))".
• Removing quotes may allow a broader search: (((( a large decrease ) OR ( a marked decrease ))) OR ( b large decrease )).
• Adding a wildcard symbol may retrieve word variants: (((("a large decrease") OR ("a marked decrease"))) OR ("b large decrease"))*.