The History view does not always show all the changes ever made to a resource because there may be thousands of changes and retrieving the entire list can take a long time. Normally you are interested in the more recent ones. That is why you can specify the criteria for the revisions displayed in the History view by selecting one of several options presented in the History dialog which is displayed when you invoke the Show History action.
all revisions of the selected resource;
only revisions between a start revision number and an end revision number;
only revisions added in a period of time like today, last week, last month, etc.;
only revisions between a start and an end date;
only revisions committed by a specified SVN user.
The toolbar of the History view has two buttons for extending the set of revisions presented in the view: Get next 50 and Get all.