Perhaps you should try some spelling variations:
"dioxide emission" » "dioxide emissions"
"toxic emissions" » "dioxin emissions", "voc emissions", "dioxide emissions"
"oxide emissions" » "dioxide emissions"
"atomic emission" » "acoustic emission"

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: (((((("toxic emissions") OR ("oxide emissions"))) OR ("atomic emission"))) OR ("dioxide emission")).
• Removing quotes may allow a broader search: (((((( toxic emissions ) or ( oxide emissions ))) or ( atomic emission ))) or ( dioxide emission )).
• Adding a wildcard symbol may retrieve word variants: (((((("toxic emissions") or ("oxide emissions"))) or ("atomic emission"))) or ("dioxide emission"))*.