Perhaps you should try some spelling variations:
"cycle regulatory relations" » "cycle regulatory regions", "cycle regular relations", "cycle regulatory functions", "cycle regulation relations", "gene regulatory relations"
"acute respiratory testing" » "acute respiratory gating", "acute respiratory training", "acute respiratory patterning"

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: (("cycle regulatory relations") OR ("acute respiratory testing")).
• Removing quotes may allow a broader search: (( cycle regulatory relations ) or ( acute respiratory testing )).
• Adding a wildcard symbol may retrieve word variants: (("cycle regulatory relations") or ("acute respiratory testing"))*.