In large companies a lot of bureaucracy. This means that they, like others, post jobs publicly, but not always review all summary and are quite slow. Therefore it is best to send your resume not via the website job search, and through the website of the company or even directly to the head of the Department in which you would like to work. If you have friends in Rosneft, it is possible to work through them. Sending (or giving) a summary remember a few days to call back to the HR Department and find out whether it is considered as you can forget about it.
Usually, such companies prefer to "grow" employees, and not to take side. So get ready because even if you have experience you will be offered a job at a not too high position. Salaries in such positions, respectively, initially are not too high, but it kompensiruet social package.
At the interview be prepared for very difficult issues. To the applicants "off the street", i.e., without a recommendation from such companies very high standards. Also important are good average grade. Studying abroad can also be a plus.
Remember, Rosneft and other large companies a lot of subsidiaries. To get a job in them easier than in the parent company. You can start with them and later try to move to the parent company. Their jobs are often located in the public domain, and there is less bureaucracy.
Rosneft, like other companies, invites students for an internship. If you are a student in a specialized high school, try to get there for practice after College. Thus, you can understand whether you like to work in such companies or not, and give a good account of themselves, to make contacts.