Perhaps you should try some spelling variations:
"_ fes decrease" » "_ _ decrease" (Expand Search), "_ fed decrease" (Expand Search), "_ es decrease" (Expand Search)
"_ fe decrease" » "_ _ decrease" (Expand Search), "_ e decrease" (Expand Search)
"5 ng decrease" » "5 _ decrease" (Expand Search), "5 g decrease" (Expand Search), "5 μg decrease" (Expand Search)
"5 a decrease" » "5 _ decrease" (Expand Search), "5 _ decreased" (Expand Search), "5 _ decreases" (Expand Search)

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"5 a decrease\") OR (((((\"_ fe decrease\") OR (\"_ fes decrease\"))) OR (\"5 ng decrease\"))))~".
• Removing quotes may allow a broader search: (( 5 a decrease ) OR ((((( _ fe decrease ) OR ( _ fes decrease ))) OR ( 5 ng decrease ))))~.
• Adding a wildcard symbol may retrieve word variants: (("5 a decrease") OR ((((("_ fe decrease") OR ("_ fes decrease"))) OR ("5 ng decrease"))))*.