Perhaps you should try some spelling variations:
"safety in chemistry, dangerous four" » "safety in chemistry, dangerous how", "safety in chemistry, dangerous good", "safety in chemistry, dangerous journey"
"safety in chemistry, dangerous both" » "safety in chemistry, dangerous how"
"safety in chemistry, dangerous dead" » "safety in chemistry, dangerous great", "safety in chemistry, dangerous a"

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: (((("safety in chemistry, dangerous four") OR ("safety in chemistry, dangerous both"))) OR ("safety in chemistry, dangerous dead")).
• Removing quotes may allow a broader search: (((( safety in chemistry, dangerous four ) or ( safety in chemistry, dangerous both ))) or ( safety in chemistry, dangerous dead )).
• Adding a wildcard symbol may retrieve word variants: (((("safety in chemistry, dangerous four") or ("safety in chemistry, dangerous both"))) or ("safety in chemistry, dangerous dead"))*.