What can I do if my supervisor does not publish my research results?

This seems like a strange situation, since it is very counterproductive for both you and your supervisor. If this is indeed common in your group, I am sure several ideas have been scooped by the time they finally get submitted. Unfortunately, I really don't have any decent idea why your supervisor would act this way.

The most important thing to do is to talk to your supervisor and don't let him/her dismiss the issue. This may seem like an aggressive approach, but you can disguise it as a learning experience, e.g. "Please tell me what is wrong with the current manuscript because I believe it is ready for submission, oh wise one". Whatever you do, remain polite.

A few approaches you can try (all of which are reasonable, so don't be shy):

• Send reminders and send them often. Ask what you can do to improve the manuscript. If your supervisor has no further suggestions to change the manuscript, ask where you can submit it to directly. Don't wait for him/her to wake up. This approach may lead to your supervisor turning it into a ping-pong match, asking you to make trivial but time-consuming extensions again and again. In this case, confront your supervisor and explain your perspective.
• If you can find an appropriate call for papers, ask permission to send the manuscript there. Calls typically have deadlines and are not necessarily a downgrade in terms of venue quality. This includes conferences and journal special issues. Having a hard deadline might help.

Finish writing the paper yourself. Send your supervisor a final draft, inviting him to submit his comments on the paper and suggest some changes.

If your supervisor does not wish to collaborate on the submission, it's possible he will be OK with you finishing and submitting the paper yourself, perhaps as the sole author. Make sure to acknowledge his capacity as your supervisor at the end of the paper, if he is not included as a co-author.

If it's your data, and you wrote the paper, you have every right to publish it by yourself as long as you offer your supervisor the chance to collaborate or object.

Best-case scenario? Your own paper gets published, or your supervisor gets jolted back to reality and collaborates with you on finishing the paper together. Worst case scenario? Your paper gets rejected (don't fret, that can happen often!), so you have to head back to your supervisor or Academia.SE for advice on re-submitting it or choosing another journal.

In a comment, OP added:

Of course we have talked to our supervisor, he just said 'ok, I will look and see if anything to add', after few weeks we asked again, and he again said 'I will look into it'.

Try to understand why your supervisor behaves likes this. Some hypotheses:

• Your supervisor prefers to spent time on some other work.
• Your supervisor has to focus on some other work for external reasons.
• Your supervisor prefers to spent time working with someone else.
• Your supervisor finds the paper boring and avoids working on it.
• Your supervisor is a perfectionist and wants to avoid publishing a non-perfect paper.
• Your supervisor has bad time-management skills and forgets to look at your paper.
• Your supervisor doesn't really want to publish this for some reason.
• ... many more possibilities ...

It is important to understand why your supervisor is behaving like this, in order to react appropriately. For example, if your supervisor has very bad time-management skills and keeps forgetting your paper, it is probably better to ask about this much more often than every few weeks.

Options for understanding your supervisor better include just asking him or her about it, or asking someone who successfully collaborated with your supervisor in the past. Maybe some former grad students of your supervisor figured out how to effectively interact with your supervisor and you can learn the trick from them.