Even with such search tools as Google, there is no universal search tool that allows you to enter a search and bring back a result list that includes all the books, magazine articles, scholarly articles, newspaper articles, government publications, and dissertations on your topic.
There are MANY search tools. Some search tools simply point you to content. Others actually contain or own the content.
Alternatively, the Library's Esearch tool functions a little like Google: it searches most of the different EMU databases and provides all the results in one list.