Perhaps you should try some spelling variations:
"50 ppm decrease" » "50 _ decrease" (Expand Search), "50 nn decrease" (Expand Search), "50 pa decreased" (Expand Search), "5 ppm decrease" (Expand Search)
"5 026 decrease" » "5 _ decrease" (Expand Search), "5 nn decrease" (Expand Search), "n 026 decrease" (Expand Search)
"50 n decrease" » "50 nn decrease" (Expand Search), "50 _ decrease" (Expand Search), "50 _ decreased" (Expand Search), "50 ns decrease" (Expand Search), "50 ng decrease" (Expand Search), "50 μ decrease" (Expand Search)
"50 a decrease" » "50 _ decrease" (Expand Search), "50 _ decreased" (Expand Search), "50 _ decreases" (Expand Search), "50 μ decrease" (Expand Search), "50 c 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: "((((\"50 ppm decrease\") OR (((\"50 n decrease\") OR (\"50 a decrease\"))))) OR (\"5 026 decrease\"))~".
• Removing quotes may allow a broader search: (((( 50 ppm decrease ) OR ((( 50 n decrease ) OR ( 50 a decrease ))))) OR ( 5 026 decrease ))~.
• Adding a wildcard symbol may retrieve word variants: (((("50 ppm decrease") OR ((("50 n decrease") OR ("50 a decrease"))))) OR ("5 026 decrease"))*.