Regarding publication in journal

[equation M]

As far I am concern, similar research paper cannot be published in different conferences. But, a research paper already published in a conference “can also be published in a journal if it is worthy of it”.

Is it true??

Sorry for my childish queries.

 

[f95toli]

Yes and no.
You can not normally publish the SAME paper in two different places (there are some rare exceptions).

However, it is perfectly normal to publish papers based on the same results in several places. What normally happens is that you publish a paper in a journal, and then you might present those results at conferences write one or more papers for conference proceedings.
There are several reasons for doing this. One is that it often takes a very long time for proceedings to be published, another is that few people actually read proceedings meaning they gave very low impact.

The "trick" here is to find a new angle or a new focus for each paper and you might e.g. show data that was not in the journal article, but was acquired at the same time.

 

[Choppy]

In my experience the conference abstracts tend to come first. You work on a project and when you have some results, you present them at a conference. This provides a great public forum for feedback from your peers. Conference abstracts tend to be "mini" papers in that they don't provide a whole lot of detail and will often only concentrate on certain specific aspects of the work.

Journal submissions tend to be bigger. They provide more details, present more results and include more discussion.

So they aren't exactly the same, but will often come out of the same project.