My paper was submitted to an international conference. I didn't pay, but they published my paper online. Can you contribute to other journals?
360 periodical network solution: on what network did you read the paper? If you read it in the following periodicals of HowNet and General Administration of Press and Publication, you can't contribute any more. If it's not a regular journal, it's just published online, then you have to ask them to judge it, otherwise the paper will be used by others, and then you can't publish it.