Perhaps you should try some spelling variations:
"5 ppm decrease" » "5 _ decrease" (Expand Search), "5 nn decrease" (Expand Search), "5 pa decreased" (Expand Search)
"50 ng decrease" » "50 nn decrease" (Expand Search), "50 _ decrease" (Expand Search), "50 we decrease" (Expand Search), "50 mg decrease" (Expand Search), "10 ng decrease" (Expand Search), "5 ng decrease" (Expand Search)
"5 nm decrease" » "5 nn decrease" (Expand Search), "5 _ decrease" (Expand Search), "5 we decrease" (Expand Search), "5 mm decrease" (Expand Search), "5 cm 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 a decrease") OR ((("50 ng decrease") OR ("5 nm decrease"))))) OR ("5 ppm decrease"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"50 a decrease\") OR (((\"50 ng decrease\") OR (\"5 nm decrease\"))))) OR (\"5 ppm decrease\"))".
• Removing quotes may allow a broader search: (((( 50 a decrease ) OR ((( 50 ng decrease ) OR ( 5 nm decrease ))))) OR ( 5 ppm decrease )).
• Adding a wildcard symbol may retrieve word variants: (((("50 a decrease") OR ((("50 ng decrease") OR ("5 nm decrease"))))) OR ("5 ppm decrease"))*.