Perhaps you should try some spelling variations:
"50 ppm decrease" » "50 ppm decreased" (Expand Search), "50 ppm increase" (Expand Search)
"5 a decrease" » "5 a decreased" (Expand Search), "5 a increase" (Expand Search)
"3d point decrease" » "3d point decreased" (Expand Search), "3d point increase" (Expand Search)
"10 ng decrease" » "10 ng decreased" (Expand Search), "10 ng increase" (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 (((\"5 a decrease\") OR (\"3d point decrease\"))))) OR (\"10 ng decrease\"))~".
• Removing quotes may allow a broader search: (((( 50 ppm decrease ) OR ((( 5 a decrease ) OR ( 3d point decrease ))))) OR ( 10 ng decrease ))~.
• Adding a wildcard symbol may retrieve word variants: (((("50 ppm decrease") OR ((("5 a decrease") OR ("3d point decrease"))))) OR ("10 ng decrease"))*.