declare
  @x xml=N'
    <doc>
      <n_doc>ФС-01-01-000272</n_doc>
      <d_start>25.02.2015</d_start>
      <date_e>31.12.2099</date_e>
      <d_term>22.07.2016</d_term>
      <mp>13</mp>
      <mp>31</mp>
      <mp>32</mp>
    </doc>
    <doc>
      <n_doc>ФС-01-01-000273</n_doc>
      <d_start>25.02.2016</d_start>
      <date_e>31.12.2098</date_e>
      <d_term>22.07.2017</d_term>
      <mp>131</mp>
      <mp>311</mp>
      <mp>321</mp>
    </doc>
    ';
;with cte as (
  select
    t.n.value('n_doc[1]', 'varchar(32)') n_doc,
    t.n.value('d_start[1]', 'varchar(10)') d_start,
    t.n.query('mp') mp
  from @x.nodes('/doc') t(n)
)
select
  e.n_doc,
  e.d_start,
  t.n.value('.', 'varchar(4)')
from cte e
cross apply e.mp.nodes('mp') t(n)