It depends on the journals, if your going for nature or palgrave journals you can see the journal date in top of the page before the article heading.
You can go to www.agentquery.com and type in publishing agents
To find the date an article was published, look for the publication date at the top or bottom of the article, check the byline for the author's name and publication date, or search for the article on the website of the publication to find the original publication date.
An online magazine article is the same as an article in a paper magazine except you can find it online, usually through the magazine's own website or through an article aggregation site. You can find an example through the given link.
To find a reliable and legitimate publishing agent online, you should look into Publishers Marketplace at www.publishersmarketplace.com. There you will find a list of publishing agents as well as their contact information so that you can further investigate whether someone will be of help to you and your piece.
Most dates are prominently displayed on the article at the top or the bottom. If the date is not on the article, you can email the writer for more details.
You can find a DOI for a research article usually on the first page of the article or in the citation information. It is a unique identifier that helps locate the article online.
In order to find out more about publishing books one could visit the local library to find a book about the subject, or speak to the staff at a publishing company to get their advice. Alternatively there are online options such as Createspace.
You're going to have to find the article online but you can still cite the work.
To get the DOI of an article, you can usually find it on the first page of the article or in the citation information. It is a unique identifier that helps locate the article online.
Well most of the time you can find it on back of the cover but some times it's on the back cover
To find an article that was posted on the Yahoo site yesterday, you need to access the site and look at the date.
You can typically find the publisher of an online news article by looking for the byline, which usually includes the author's name and often the name of the publication or news organization. Additionally, you can scroll to the bottom of the article to find information about the publisher or check the "About" section of the news website.