Perhaps you should try some spelling variations:
"descending control" » "understanding control"
"descending colon" » "ascending colon", "descending chain", "descending down"
"descending motor" » "decoding motor", "descending aortic", "descending aorta"

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: (("descending colon") OR ((("descending motor") OR ("descending control")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"descending colon\") or (((\"descending motor\") OR (\"descending control\"))))".
• Removing quotes may allow a broader search: (( descending colon ) or ((( descending motor ) OR ( descending control )))).
• Adding a wildcard symbol may retrieve word variants: (("descending colon") or ((("descending motor") OR ("descending control"))))*.