As for the structure, it's not common English (not common spoken English). It's very professional/clinical. Nat rephrased it well, that would be a normal way of saying the same thing. This would generally follow a statement about the lack of signs, which would make it easier to understand. Example: "There aren't many signs of recovery. What signs there are of recovery are patchy at best." In other words: "There aren't many signs of recovery. And the signs we do have - they aren't very reliable."

It means: There are very few signs of recovery. The signs that do exist are not that strong.