'subtle evidence' is an appropriate phrase to use in written English.
You can use it when you want to describe something that is not immediately obvious, but which may be still perceived. For example, "We found subtle evidence that the suspect had been at the scene of the crime."
Yet there is subtle evidence that we're seeing a labor-intensive profit-making paradise, with sugar and tobacco as early export commodities, and oil coming later.
In most persons who experience an acute myocardial infarction, the circulation remains adequate, and only by subtle evidence such as rales (abnormal respiratory sounds) in the lungs or a gallop rhythm of the heartbeat may the evidence of some minor degree of heart failure be detected.
ERPs from IDMs demonstrated subtle evidence of recognition memory impairments.
There is already subtle evidence that environmental change is underway at Nikkō.
Again, the analysis provided some subtle evidence of debris-induced anomalies but it was not convincing.
High-resolution manometry (HRM) allows for reliable evaluation of the lower esophageal sphincter (LES) in detail, including subtle evidence of a hiatus hernia.
The resolution, however subtle, is evidence of how last year's outbreak of the West Nile virus is affecting public health policy and the activities of city agencies.
The computer might never replace the human expert but digital processing is superior to film reading when looking for subtle diagnostic evidence.
The subtlest of evidence can clarify the picture, he said.
They were moist, the curry flavoring subtle but in evidence.
Oliver James's phrase might not have been the most subtle, but the evidence he subsequently brought to bear was compelling.
