Both are common and correct. Their proper usage will depend upon the context in which you employ them.
To read a magazine or to read the magazine?
Which variant is more common (or correct)?
Have you read the paper today?
***** NOT A TEACHER *****
(1) Great question!
(2) Mother: Can you help me prepare dinner, please?
Daughter: Sorry, Mom. But I'm reading a magazine now.
Mother: I don't care what you're reading! Get into the kitchen right now, young lady!
***
(3) Son: Hey, Dad, have you had time to read the copy of Newsweek that I gave you
yesterday?
Father: I am reading the magazine [that you gave me] right now. ["The" = something like "that."]
***
Mother: Can you help me prepare dinner, please?
Daughter: I'm busy, Mom, reading the newspaper. [I think that 'the" would be
more likely because -- at least in the United States -- most people read only one
newspaper -- the [that] newspaper that comes to the house every morning. On the other
hand, magazines -- in theory -- are more plentiful, so you would not refer to the
magazine, except in the case of my son/father dialogue.]
***
People usually ask, "Have you read the paper today?" [When they ask this,
they are not necessarily referring to a specific newspaper. It's almost like: Have
you read any newspaper today?]
But people would look at you very strangely if you asked "Have you read the
magazine today?" [Again, unless you were referring to a specific magazine.]
There are, unfortunately, rather more than three 'special cases'.Special case-2: Use with transportation:
Eg: The railway, the subway etc
We normally go by train, bus, tram, tube etc; we don't use an article. We can, however, 'take a/the train, bus, tram'.
Special case-3: Use with forms of entertainment:
Eg: The ballet etc.
Special case-2: Use with transportation:
Eg: The railway, the subway etc
We normally go by train, bus, tram, tube etc; we don't use an article.
5Sorry, 5jj. I didn't elaborate it. My elaboration with the first special use holds good for this use too. I.e, When we refer to the whole system we say 'the railway', 'the subway' etc,
I don't think we do very often. When I talk about a system, I use the word 'system': "The German railway system is rather more efficient than the British (railway system)". I would use 'the railway' only if talking about the means of transport involving locomotives running on rails: "The arrival of the railway meant that people could at last travel long distances faster the ancient Romans".
but when we [STRIKE]be[/STRIKE] are specific, we say, train, bus and the like[STRIKE]s[/STRIKE].