Problem matching Arabic Text in WHERE clause in SQL Server

i have a problem when selecting data from sql database based on arabic word

this is the code i use 

        string strSQLconnection = @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\MedicalNetwork.mdf;Integrated Security=True;User Instance=True";
        SqlConnection sqlConnection = new SqlConnection(strSQLconnection);
        SqlCommand sqlCommand = new SqlCommand("select * from Hospitals where Town = 'المهندسين'", sqlConnection);
        sqlConnection.Open();
        SqlDataReader reader = sqlCommand.ExecuteReader();
        GridView1.DataSource = reader;
        GridView1.DataBind();

any onw knows why ???