Slideshare is a community that allows people to upload and share slides and other resources. Its aim is to share knowledge online.
For example, this is a presentation on plural nouns in English:
This is a book on phrasal verbs in context:
This one could help you improve your vocabulary:
This is how it looks when you search for a topic:
First of all, you have to write the topic you are interested in (on the top), then you can click on the search icon. The image above shows you how it will appear on your screen. After you’ve clicked on the “search” button, you can change the language (look at the red arrow on the right). Thanks to this option, you will be able to find resources not only in English but also in other languages.