Perhaps you should try some spelling variations:
"50 nn decrease" » "50 a decrease" (Expand Search), "50 mean decrease" (Expand Search), "50 gy decreased" (Expand Search), "50 ns decrease" (Expand Search), "50 ng decrease" (Expand Search), "50 n decrease" (Expand Search)
"5 ng decrease" » "5 a decrease" (Expand Search), "5 we decrease" (Expand Search), "5 gy decreased" (Expand Search), "5 mg decrease" (Expand Search), "5 g decrease" (Expand Search), "5 kg decrease" (Expand Search)
"5 nm decrease" » "5 a decrease" (Expand Search), "5 we decrease" (Expand Search), "5 gy decreased" (Expand Search), "5 mm decrease" (Expand Search), "5 cm decrease" (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: "((\"50 nn decrease\") OR (((((\"5 ng decrease\") OR (\"50 _ decrease\"))) OR (\"5 nm decrease\"))))~".
• Removing quotes may allow a broader search: (( 50 nn decrease ) OR ((((( 5 ng decrease ) OR ( 50 _ decrease ))) OR ( 5 nm decrease ))))~.
• Adding a wildcard symbol may retrieve word variants: (("50 nn decrease") OR ((((("5 ng decrease") OR ("50 _ decrease"))) OR ("5 nm decrease"))))*.