Perhaps you should try some spelling variations:
"5 mean decrease" » "5 a decrease" (Expand Search), "_ mean decrease" (Expand Search), "a mean decrease" (Expand Search), "i mean decrease" (Expand Search)
"50 ppm decrease" » "50 _ decrease" (Expand Search), "50 a decrease" (Expand Search), "50 nn decrease" (Expand Search), "5 ppm decrease" (Expand Search)
"10 ng decrease" » "10 nn decrease" (Expand Search), "10 _ decrease" (Expand Search), "10 a decrease" (Expand Search), "100 ng decrease" (Expand Search), "10 mg decrease" (Expand Search), "10 nm decrease" (Expand Search)

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 ("10 ng decrease"))) OR ("5 mean decrease"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"50 ppm decrease\") OR (\"10 ng decrease\"))) OR (\"5 mean decrease\"))".
• Removing quotes may allow a broader search: (((( 50 ppm decrease ) OR ( 10 ng decrease ))) OR ( 5 mean decrease )).
• Adding a wildcard symbol may retrieve word variants: (((("50 ppm decrease") OR ("10 ng decrease"))) OR ("5 mean decrease"))*.