追溯 zhuīsù, lit. to go upstream/to trace sth back to/to date from 回溯 huísù, to recall/to look back upon 溯源 sùyuán, to investigate the origin of sth/to trace a river upstream back to its source 溯 sù, [遡], to go upstream/to trace the source, variant of 溯[sù] 寻根溯源 xúngēnsùyuán, [尋根溯源], see 追根溯源[zhuī gēn sù yuán] 推本溯源 tuīběnsùyuán, to go back to the source 推溯 tuīsù, to trace back to 追本溯源 zhuīběnsùyuán, to trace sth back to its origin 追根溯源 zhuīgēnsùyuán, to pursue sth back to its origins/to trace back to the source/to get to the bott... 逆流溯源 nìliúsùyuán, to go back to the source