Perhaps you should try some spelling variations:
"diseases drugs effective." » "diseases groups effective.", "diseases drugs affecting.", "diseases davis effective.", "disease drugs effective.", "disease drug effective.", "diseases dogs effective."
"diseases drugs effectss." » "disease drugs effectss.", "disease drug effectss.", "diseases dogs effectss.", "diseases drugs effects.", "diseases drug effects.", "diseases drug effectors."
"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.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("diseases drugs effectss.") OR ("diseases drugs effective."))) OR ("diseases drug effect."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"diseases drugs effectss.\") OR (\"diseases drugs effective.\"))) OR (\"diseases drug effect.\"))".
• Removing quotes may allow a broader search: (((( diseases drugs effectss. ) OR ( diseases drugs effective. ))) OR ( diseases drug effect. )).
• Adding a wildcard symbol may retrieve word variants: (((("diseases drugs effectss.") OR ("diseases drugs effective."))) OR ("diseases drug effect."))*.