Used when one must dig into information or a topic to find something hidden or not obvious.

Deep Investigation

Emphasizes that the object of the search is difficult to locate and requires effort.

Hard to Find

Highlights that 'search out' is a deliberate and focused action, not a casual look.

Highlights the aspect of uncovering something not immediately apparent through efforts.

Often used in contexts where something needs to be solved or explained, like a mystery.

Implies an expectation of finding a result or answer, not just the act of looking.