Perhaps you should try some spelling variations:
"5 ppm decrease" » "5 _ decrease" (Expand Search), "5 a decrease" (Expand Search), "5 nn decrease" (Expand Search)
"5 non decrease" » "5 nn decrease" (Expand Search), "5 point decrease" (Expand Search), "5 note decreased" (Expand Search), "5 nonn decrease" (Expand Search), "5 no_ decrease" (Expand Search), "5 noa decrease" (Expand Search), "_ non decrease" (Expand Search), "a non decrease" (Expand Search), "e non decrease" (Expand Search), "15 non decrease" (Expand Search), "5 nmon decrease" (Expand Search)
"5 n decrease" » "5 nn decrease" (Expand Search), "5 _ decrease" (Expand Search), "5 a decrease" (Expand Search), "15 n decrease" (Expand Search), "5 nm decrease" (Expand Search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("5 ppm decrease") OR ((("5 n decrease") OR ("5 non decrease"))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"5 ppm decrease\") OR (((\"5 n decrease\") OR (\"5 non decrease\"))))".
• Removing quotes may allow a broader search: (( 5 ppm decrease ) OR ((( 5 n decrease ) OR ( 5 non decrease )))).
• Adding a wildcard symbol may retrieve word variants: (("5 ppm decrease") OR ((("5 n decrease") OR ("5 non decrease"))))*.