Perhaps you should try some spelling variations:
"5 ppm decrease" » "5 _ decrease" (Expand Search)
"5 wt decrease" » "5 _ decrease" (Expand Search), "_ wt decrease" (Expand Search), "5 ht decrease" (Expand Search), "2 wt decrease" (Expand Search)
"9 a decrease" » "9 _ decrease" (Expand Search), "9 _ decreased" (Expand Search), "9 _ decreases" (Expand Search), "19 a decrease" (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 ppm decrease\") OR (((\"9 a decrease\") OR (((\"_ e decrease\") OR (\"5 wt decrease\"))))))~".
• Removing quotes may allow a broader search: (( 5 ppm decrease ) OR ((( 9 a decrease ) OR ((( _ e decrease ) OR ( 5 wt decrease ))))))~.
• Adding a wildcard symbol may retrieve word variants: (("5 ppm decrease") OR ((("9 a decrease") OR ((("_ e decrease") OR ("5 wt decrease"))))))*.