There are a ton of third party apps for this.
If you use SharePoint with SQL server then you can enable full text search for the site.
Otherwise there is not a native way to do this. You could try writing some code in ASP.Net if you know that, otherwise I would say go with the 3rd party tools.
Note that those tools are for searching a web site and not the entire server. You may need to alter your approach/site design.
I hope you find this post helpful.
Regards,
Mark