Perhaps you should try some spelling variations:
"5 ppm decrease" » "5 _ decrease" (Expand Search)
"50 ng decrease" » "50 _ decrease" (Expand Search), "10 ng decrease" (Expand Search), "50 μg decrease" (Expand Search), "50 _g decrease" (Expand Search), "50 ig decrease" (Expand Search)
"50 n decrease" » "50 _ decrease" (Expand Search), "50 _ decreased" (Expand Search), "50 _ decreases" (Expand Search), "50 i decrease" (Expand Search)
"_ e decrease" » "_ _ decrease" (Expand Search), "_ _ decreased" (Expand Search), "_ _ decreases" (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: (("5 ppm decrease") OR ((((("50 n decrease") OR ("50 ng decrease"))) OR ("_ e decrease"))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"5 ppm decrease\") OR (((((\"50 n decrease\") OR (\"50 ng decrease\"))) OR (\"_ e decrease\"))))".
• Removing quotes may allow a broader search: (( 5 ppm decrease ) OR ((((( 50 n decrease ) OR ( 50 ng decrease ))) OR ( _ e decrease )))).
• Adding a wildcard symbol may retrieve word variants: (("5 ppm decrease") OR ((((("50 n decrease") OR ("50 ng decrease"))) OR ("_ e decrease"))))*.