You will probably find some information on the mental effects of family violence on children in Lexis-Nexis, but it will most likely be popular information. Subject headings lend authority to a database. When searching a book by subject heading in a library catalog, it must be searched only in the subject field only. If you link two terms together with AND, you are asking the database to look for records where both terms appear. However, you may not always retrieve the results you expect.
Scholarly publications tend to cater to very focused, academic audiences.
Articles are written by experts for fellow experts. Most often, specialized language will be used in these publications. This is one feature of a scholarly publication, but not the only one. The key word here is original. Criteria for original research will vary from field to field.