Perhaps you should try some spelling variations:
"50 pp decrease" » "50 _ decrease" (Expand Search)
"5 μ decrease" » "5 _ decrease" (Expand Search), "5 _ decreased" (Expand Search), "5 _ decreases" (Expand Search), "5 μg decrease" (Expand Search)
"40 a decrease" » "40 _ decrease" (Expand Search), "40 _ decreased" (Expand Search), "40 _ decreases" (Expand Search)
"4 a decrease" » "4 _ decrease" (Expand Search), "4 _ decreased" (Expand Search), "4 _ decreases" (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 ((((("40 a decrease") OR ("4 a decrease"))) OR ("5 μ decrease"))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"50 pp decrease\") OR (((((\"40 a decrease\") OR (\"4 a decrease\"))) OR (\"5 μ decrease\"))))*".
• Removing quotes may allow a broader search: (( 50 pp decrease ) OR ((((( 40 a decrease ) OR ( 4 a decrease ))) OR ( 5 μ decrease ))))*.