When using the search unexpected search results are shown. For example if searching for friedrichs records that contain Friedrich are returned.
Why are these additional results returned and how can they be excluded?
The search is conducted using Microsoft SQL Server Full Text Index. This uses what are called inflectional forms of words when searching. These include singular and plural forms. More details can be found on this page https://msdn.microsoft.com/en-us/library/ms142583.aspx.
When searching for friedrichs in this case it is also searching for the singular form friedrich.
If you only want the exact match then you can wrap the word in quotes, i.e. "friedrichs". This will stop results for the singular friedrich being returned.