You can do this by creating a new column to your table that contains the id of a row:
Add a new field and name it for example ID (in capitals)
The type of the field is formula and the formula is: row_id()
Now you can create a new view and set a filter to that view. In the filter, you can determine which id’s must be shown. For example: only rows with an id smaller then 50.000. Finally, you can export the view.