Perhaps you should try some spelling variations:
"pollutants dispersion reduction" » "pollutant dispersion reduction", "pollution dispersion reduction", "pollutants detection reduction", "pollutants dispersion prediction", "pollutants dispersion predictions", "pollutants dispersion equation"
"pollutants dispersion relation" » "pollutant dispersion relation", "pollution dispersion relation", "pollutants detection relation", "pollutants dispersion relations"
"pollutant diffusion reflection" » "pollutant discussion reflection", "pollutant diffusion reaction", "pollutant diffuse reflection", "pollutant dispersion reflection", "constant diffusion reflection"
"pollutants dimension reduction" » "pollutants discussion reduction", "pollutant dispersion reduction", "pollutants detection reduction", "pollutants dimensionality reduction"

Try widening your search to All Fields.

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("pollutant diffusion reflection") OR ((((("pollutants dispersion reduction") OR ("pollutants dispersion relation"))) OR ("pollutants dimension reduction")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"pollutant diffusion reflection\") or (((((\"pollutants dispersion reduction\") OR (\"pollutants dispersion relation\"))) or (\"pollutants dimension reduction\"))))".
• Removing quotes may allow a broader search: (( pollutant diffusion reflection ) or ((((( pollutants dispersion reduction ) OR ( pollutants dispersion relation ))) or ( pollutants dimension reduction )))).
• Adding a wildcard symbol may retrieve word variants: (("pollutant diffusion reflection") or ((((("pollutants dispersion reduction") OR ("pollutants dispersion relation"))) or ("pollutants dimension reduction"))))*.