The words underlined are used in a variety of situations.  The police may do a complete investigation.  A person may look in every conceivable location for something that was lost.  A student may read extensively about a subject before writing a report.

他做研究的時候，可說是「上窮碧落下黃泉」（翻遍了所有資料）。

Left no stone unturned字面義為：翻遍每塊石頭。舉凡研究生博覽群籍、警方做詳盡無遺的調查、或你我翻箱倒櫃找尋失落的物品等，皆可用此片語來形容。