Perhaps you should try some spelling variations:
decrease purification » decrease nitrification (Expand search), protease purification (Expand search), acylase purification (Expand search)
purification process » purificacao processo (Expand search), desertification process (Expand search), identification process (Expand search)
decrease the » decreases the (Expand search), decrease in (Expand search), decrease of (Expand search)
the decrease » to decrease (Expand search), and decrease (Expand search)
decrease can » decrease in (Expand search), decrease and (Expand search), decrease at (Expand search)
can decrease » can increase (Expand search), and decrease (Expand search), to decrease (Expand search)

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

• Removing quotes may allow a broader search: (( decrease the decrease purification process ) OR ( decrease OR decrease can decrease ))~.