Perhaps you should try some spelling variations:
"5 ppm decrease" » "5 _ decrease" (Expand Search)
"5 we decrease" » "5 _ decrease" (Expand Search), "5 w_ decrease" (Expand Search), "5 w_ decreased" (Expand Search), "5 w_ decreases" (Expand Search), "_ we decrease" (Expand Search)
"5 a decrease" » "5 _ decrease" (Expand Search), "5 _ decreased" (Expand Search), "5 _ decreases" (Expand Search)
"_ e decrease" » "_ _ decrease" (Expand Search), "_ _ decreased" (Expand Search), "_ _ decreases" (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 a decrease\") OR (\"5 ppm decrease\"))) OR (((\"5 we decrease\") OR (\"_ e decrease\"))))~".
• Removing quotes may allow a broader search: (((( 5 a decrease ) OR ( 5 ppm decrease ))) OR ((( 5 we decrease ) OR ( _ e decrease ))))~.
• Adding a wildcard symbol may retrieve word variants: (((("5 a decrease") OR ("5 ppm decrease"))) OR ((("5 we decrease") OR ("_ e decrease"))))*.