Substring search only searches from the start of word strings. (Perhaps by design?)

Searching the string "Dea", for instance, will return anything with the word "Death" or "Dead", but searching "ead" will return nothing. I noticed this when I had purchased a duplicate copy of "Re-Cycle". I had searched for "Cycle", thinking it was a full substring search, but since it's considered a single word, it did not find it. Thankfully, I'm only out a dollar and it was a charity shop, so at least it goes to a good cause.