Here's a video showing how to do a search in Loeb Classic Library.
Note: The demo of the search starts at about 3:23 into the video so, start there.
LOEB: Ancient history, with its paucity of sources, is unusually dependent on the writings of ancient Greek and Roman authors which have survived to our present, sometimes only in fragments. While reading them in their original languages is superior, for the rest of us, “[t]he Lobe Classical Library has been a mainstay of anglophone Classics for many years." Long a familiar mainstay of library collections in its iconic undersized hardback editions (“Red for Romans/Green for Greeks”), it has now been digitized.
Alkek has the full digital collection here.
Library also owns print copies, Check the library catalog for specific titles