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