Perhaps you should try some spelling variations:
"5 ppm decrease" » "5 _ decrease" (Expand Search), "5 a decrease" (Expand Search), "5 pa decreased" (Expand Search)
"5 non decrease" » "5 point decrease" (Expand Search), "5 note decreased" (Expand Search), "5 fold decrease" (Expand Search), "_ non decrease" (Expand Search), "a non decrease" (Expand Search), "e non decrease" (Expand Search)
"5 nn decrease" » "5 _ decrease" (Expand Search), "5 a decrease" (Expand Search), "5 mean decrease" (Expand Search), "59 nn decrease" (Expand Search), "5 n decrease" (Expand Search), "5 ng decrease" (Expand Search)
"5 nm decrease" » "5 _ decrease" (Expand Search), "5 a decrease" (Expand Search), "5 we decrease" (Expand Search), "5 mm decrease" (Expand Search), "5 cm decrease" (Expand Search)

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

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