Perhaps you should try some spelling variations:
"50 ppm decrease" » "50 _ decrease" (Expand Search)
"_ web decrease" » "_ _ decrease" (Expand Search)
"10 ng decrease" » "10 _ decrease" (Expand Search), "100 ng decrease" (Expand Search), "10 μg decrease" (Expand Search)
"5 mg decrease" » "5 _ decrease" (Expand Search), "25 mg decrease" (Expand Search), "_ mg decrease" (Expand Search), "5 g 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 mg decrease") OR ("_ web decrease"))))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"50 ppm decrease\") OR (((\"10 ng decrease\") OR (((\"5 mg decrease\") OR (\"_ web decrease\"))))))*".
• Removing quotes may allow a broader search: (( 50 ppm decrease ) OR ((( 10 ng decrease ) OR ((( 5 mg decrease ) OR ( _ web decrease ))))))*.