You can backup databases, but not (natively) tables. Depends what you want to do with them. If you want a rough and ready snapshot (say you want to develop on the table, and every so often refresh the data) then
SELECT * INTO myBackupTable FROM mySourceTable
. Or you can use BCP to output the contents of the table onto the filesystem, but you will need to also script out the schema, indexes, constraints etc for a full "backup".