Perhaps you should try some spelling variations:
ppm decrease » a decrease (Expand Search), nn decrease (Expand Search), pa decreased (Expand Search)
ns decrease » nn decrease (Expand Search), a decrease (Expand Search), we decrease (Expand Search)
ng decrease » nn decrease (Expand Search), a decrease (Expand Search), we decrease (Expand Search)
50 ppm » 5 ppm (Expand Search)
50 ns » 50 ms (Expand Search)
10 ng » 100 ng (Expand Search), 10 mg (Expand Search), 10 nm (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 ns decrease ) OR ( 10 ng decrease ))))) OR ( 50 _ decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (((( 50 ppm decrease ) OR ((( 50 ns decrease ) OR ( 10 ng decrease ))))) OR ( 50 _ decrease ))*.