Perhaps you should try some spelling variations:
during depressed » during depressive (Expand search), during repressive (Expand search), feeling depressed (Expand search)
decrease nitrate » decrease nitrogen (Expand search), increases nitrate (Expand search), decreases nitrogen (Expand search)
nitrate contents » nitrate content (Expand search), nitrite content (Expand search), nitrogen contents (Expand search)
decrease during » increase during (Expand search), increases during (Expand search), increased during (Expand search)
decrease with » decreases with (Expand search), increase with (Expand search), decrease in (Expand search)
with decrease » with decreased (Expand search), with deceased (Expand search), with increase (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: "(( decrease with decrease during depressed ) OR ( decrease _ decrease nitrate contents ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease with decrease during depressed ) OR ( decrease _ decrease nitrate contents ))*.