I find the Google Scholar extension very useful. It lets you lookup scholarly articles as you browse the web.
This extension adds a browser button for easy access to Google Scholar from any web page. By clicking the button you can find full text on the web or in your university library. You can also highlight the title of any text on a web page you are reading, and then tap the Google Scholar button to search. You can also quickly and easily obtain references in different formats as well as their citations.
Highly recommended for report writing and for researchers and students alike!