Where do I look instead? - Special search engines

Now what? How do you efficiently search the Internet for scientific sources? Special search engines are more useful than general search engines. These are usually limited to selected content or document types, but they cover them more completely.

To find such special search engines, you can either first use a general search engine or search via the database information system DBIS (cf. unit 2). When typing in "search engine", a corresponding hit list is displayed.