Tasks and search results now can be exported to CSV. To do this you need to go to the Tasks page, do the search and then click "Export" item in "More Actions" listbox.
Exported CSV will have the same format as the one exported from the Sprint. Therefore it is possible to import it back to sprints. Please note that when importing tasks to sprint, tasks that already exist will be updated and their order and hierarchy will be broken because tasks list and search results maintain neither order nor hierarchy. At the same time it is safe to import such CSV into the empty sprints in the same project or any sprints in another project. This means that you can use export/import to easily copy tasks between projects in Acunote.