Perhaps you should try some spelling variations:
"_ feb decrease" » "_ _ decrease" (Expand Search), "_ web decrease" (Expand Search), "_ fed decrease" (Expand Search), "_ fes decrease" (Expand Search), "_ eb decrease" (Expand Search)
"50 ng decrease" » "50 _ decrease" (Expand Search), "10 ng decrease" (Expand Search), "50 μg decrease" (Expand Search)
"_ fe decrease" » "_ _ decrease" (Expand Search), "_ e decrease" (Expand Search)
"50 a decrease" » "50 _ decrease" (Expand Search), "50 _ decreased" (Expand Search), "50 _ decreases" (Expand Search), "5 a decrease" (Expand Search), "50 i 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 ng decrease") OR ((((("_ fe decrease") OR ("_ feb decrease"))) OR ("50 a decrease"))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"50 ng decrease\") OR (((((\"_ fe decrease\") OR (\"_ feb decrease\"))) OR (\"50 a decrease\"))))*".
• Removing quotes may allow a broader search: (( 50 ng decrease ) OR ((((( _ fe decrease ) OR ( _ feb decrease ))) OR ( 50 a decrease ))))*.