From Longman Dictionary of Contemporary Englishleave no stone unturnedleave no stone unturnedto do everything you can in order to find something or to solve a problem Jarvis left no stone unturned in his search to find the ring. → stone
Examples from the Corpus
leave no stone unturned• If a solution can be found, Mr Danby, I shall leave no stone unturned until I have found it.• Union leaders have promised to leave no stone unturned in their search for a way to keep the factory open.• Henry was a boy who left no stone unturned, and he got a torch and shone the beam inside. 