Perhaps you should try some spelling variations:
"diseases dna effect." » "disease dna effect.", "diseases donna effect.", "diseases dhea effect.", "diseases a effect.", "diseases ia effect.", "diseases usa effect."
"diseases kra effect." » "diseases a effect.", "diseases k.j effect.", "diseases k effect.", "diseases ia effect.", "diseases usa effect."
"diseases drug effect." » "diseases drug effects.", "diseases drag effect.", "diseases drugs effects."

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: (((("diseases dna effect.") OR ("diseases kra effect."))) OR ("diseases drug effect."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"diseases dna effect.\") OR (\"diseases kra effect.\"))) or (\"diseases drug effect.\"))~".
• Removing quotes may allow a broader search: (((( diseases dna effect. ) OR ( diseases kra effect. ))) or ( diseases drug effect. ))~.
• Adding a wildcard symbol may retrieve word variants: (((("diseases dna effect.") OR ("diseases kra effect."))) or ("diseases drug effect."))*.