With Google Scholar you can search across many disciplines and sources: articles, theses, books, abstracts, patents and court opinions, from academic publishers, professional societies, online repositories, universities and other web sites. The coverage is not limited to certain disciplines or certain journals.
However, what’s indexed by Google (and thus searchable) depends not only on the content, but also on technical issues. For example, one of the requirements of Google is that users must see at least the complete abstract or the first full page of the article. Not all publishers allow this. That makes it hard to know the boundaries of Google Scholar – what’s included and what’s not? What's included today, may be deleted next week.
It's also possible that different versions of one article are indexed by Google. That means that the citations in this article are also indexed more than once. It's even possible that in the officially published version of an article a particular citation used in a preprint version, isn't cited anymore. In Web of Science or Scopus this citation doesn't count, but in Google Scholar it does.
So, be very careful when using bibliometric information in Google Scholar!
Access
To access Google Scholar no additional subscriptions or logins are required. To make the most of using Google Scholar, we advise you to activate the Library Links for the Erasmus University. You can find this option under the Settings in Google Scholar. With this option activated, you'll see a link 
next to articles the EUR has access to. This is the link resolver of the EUR - when you click this link you'll be guided to the full-text of the article in one of the databases the University Library subscribes to.