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 mg decrease" » "5 _ decrease" (Expand Search), "5 nn decrease" (Expand Search), "5 mean decrease" (Expand Search), "5 mm decrease" (Expand Search)
"5 we decrease" » "5 _ decrease" (Expand Search), "5 nn decrease" (Expand Search), "5 mean decrease" (Expand Search), "_ we decrease" (Expand Search), "5 wt decrease" (Expand Search), "5 w 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)

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("50 ppm decrease") OR ((("5 mg decrease") OR ("5 we decrease"))))) OR ("50 a decrease"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"50 ppm decrease\") OR (((\"5 mg decrease\") OR (\"5 we decrease\"))))) OR (\"50 a decrease\"))".
• Removing quotes may allow a broader search: (((( 50 ppm decrease ) OR ((( 5 mg decrease ) OR ( 5 we decrease ))))) OR ( 50 a decrease )).
• Adding a wildcard symbol may retrieve word variants: (((("50 ppm decrease") OR ((("5 mg decrease") OR ("5 we decrease"))))) OR ("50 a decrease"))*.