Perhaps you should try some spelling variations:
"5 ppm decrease" » "5 _ decrease" (Expand Search)
"10 ng decrease" » "10 _ decrease" (Expand Search), "100 ng decrease" (Expand Search), "10 μg decrease" (Expand Search)
"5 wt decrease" » "5 _ decrease" (Expand Search), "_ wt decrease" (Expand Search), "5 ht decrease" (Expand Search), "i wt decrease" (Expand Search)
"2 wt decrease" » "2 _ decrease" (Expand Search), "_ wt decrease" (Expand Search), "i wt 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: (("5 ppm decrease") OR ((("10 ng decrease") OR ((("5 wt decrease") OR ("2 wt decrease"))))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"5 ppm decrease\") OR (((\"10 ng decrease\") OR (((\"5 wt decrease\") OR (\"2 wt decrease\"))))))*".
• Removing quotes may allow a broader search: (( 5 ppm decrease ) OR ((( 10 ng decrease ) OR ((( 5 wt decrease ) OR ( 2 wt decrease ))))))*.