Top 10 & Last 5

I would like to show the Top10 & Last 5 of a table in one query. I tried

SELECT TOP 5 dbo_tblStatistikTmp_sb_Index.IQ, dbo_tblStatistikTmp_sb_Index.Index, dbo_tblStatistikTmp_sb_Index.Anzeige
FROM dbo_tblStatistikTmp_sb_Index
WHERE (((dbo_tblStatistikTmp_sb_Index.Technik_Anzahl)>50))
ORDER BY dbo_tblStatistikTmp_sb_Index.IQ;
 UNION
SELECT TOP 10 dbo_tblStatistikTmp_sb_Index.IQ, dbo_tblStatistikTmp_sb_Index.Index, dbo_tblStatistikTmp_sb_Index.Anzeige
FROM dbo_tblStatistikTmp_sb_Index
WHERE (((dbo_tblStatistikTmp_sb_Index.Technik_Anzahl)>50))
ORDER BY dbo_tblStatistikTmp_sb_Index.IQ DESC;

which gives me back the wrong results. Each query alone brings back the correct results, but in the UNION it doesn't work. Any idea why?
thx
Kongta