yes, ChrisM's query is simple aswell it is more efficient and Optimized too..
--Estimated Subtree Cost = 0.0034222 (to calculate 21.6 rows)
select Field from #tempunpivot UNPIVOT (Field for ColumnName IN ([unic],[nrc],[nr_tel],[id_stud])) unpvt
--Estimated Subtree Cost = 0.0034131 (to Calculate 24 rows)
FROM #tempunpivot t
CROSS APPLY (VALUES (unic), (nrc), (nr_tel), (id_stud)) d (NewColumn)
I would like to stick with "Cross Apply", Query thanks to ChrisM & Mouris..