Line chart scope is to show readable data on different screen. To achieve this scope line chart automatically zoom on a readable detail and show the whole data in the mini chart below. If you have enough space to stretch the chart, it'll show the whole data.
An alternative is the use of combo chart, which has a different scope, but should work in your case.
Thanks Vincenzo. I have just tried the combo chart.
Actually, the combo Chart also does not offer the feature that I am looking for. at least the line chart show the whole data below in the small scroll bar, while the combo chart does not. There is a scroll bar to explore all the data when the chart is really small but it is only a normal scroll bar with a dragging button, it does not showing the whole data as the line chart does.