Perhaps you should try some spelling variations:
"pollutant diffusion reduction" » "pollutant dispersion reduction", "constant diffusion reduction", "pollutants dispersion reduction", "pollutant diffusion prediction", "pollutant diffusion reflection", "pollutant diffusion equation"
"pollutant diffusion reaction" » "pollutant dispersion reaction", "constant diffusion reaction", "pollutants dispersion reaction", "pollutant diffusion equation"

Try widening your search to All Fields.

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: "((\"pollutant diffusion reduction\") OR (\"pollutant diffusion reaction\"))".
• Removing quotes may allow a broader search: (( pollutant diffusion reduction ) OR ( pollutant diffusion reaction )).
• Adding a wildcard symbol may retrieve word variants: (("pollutant diffusion reduction") OR ("pollutant diffusion reaction"))*.