Perhaps you should try some spelling variations:
"50 nsn decrease" » "50 nn decrease" (Expand Search), "50 mean decrease" (Expand Search), "50 use decreased" (Expand Search), "50 nsnn decrease" (Expand Search), "50 ns_ decrease" (Expand Search), "50 nsa decrease" (Expand Search), "50 ns decrease" (Expand Search), "50 nssn decrease" (Expand Search), "50 μsn decrease" (Expand Search), "50 _sn decrease" (Expand Search)
"50 ng decrease" » "50 nn decrease" (Expand Search), "50 _ decrease" (Expand Search), "50 a decrease" (Expand Search), "50 mg decrease" (Expand Search), "10 ng decrease" (Expand Search), "5 ng decrease" (Expand Search), "50 nsg decrease" (Expand Search), "50 μg decrease" (Expand Search), "50 _g decrease" (Expand Search)
"50 n decrease" » "50 nn decrease" (Expand Search), "50 _ decrease" (Expand Search), "50 a decrease" (Expand Search), "50 ns decrease" (Expand Search), "50 μ 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 nsn decrease\") OR (((\"50 n decrease\") OR (\"50 ng decrease\"))))~".
• Removing quotes may allow a broader search: (( 50 nsn decrease ) OR ((( 50 n decrease ) OR ( 50 ng decrease ))))~.
• Adding a wildcard symbol may retrieve word variants: (("50 nsn decrease") OR ((("50 n decrease") OR ("50 ng decrease"))))*.