During writing my academic paper, I need to cite a definition in a scientific paper. The other part of the paper, is irrelevant to my work.
I have been advised that if you will cite a paper, you need to read that paper entirely. But in this case, it seems useless to do so.
It also happened a few times when I wanted to cite from some books.
No, you don't have to read the whole paper. If you think you do, ask yourself this:
do you also have to read all papers cited in the paper?
For example, I recently needed to know a certain function of n. Some computer experimentation suggested that it might be 3*2^n, let's say. Then I found a paper published in a reputable journal that claimed to prove exactly that. As the reasons why it was 3*2^n were probably rather unrelated to what I was trying to do, I cited them but did not check their proof.
On balance, I think that making every author read every paper they ever cite would slow down the progress of science.
Caveat: this may be field-dependent. For instance, if the paper can be thought of as consisting of just one long definition, then yes, one should read the whole thing.
You need to read and understand enough of the material to feel comfortable relying on it to be authoritative for the material you are citing. If you are using a dictionary to provide a definition of a word, you don't need to read the whole dictionary. If you are citing a journal article to provide a definition of a scientific concept, it's probably in your interest to read the whole thing to be sure that those authors give and correctly apply that definition. Even if they define it correctly, if their use is misleading, wrong, or otherwise dubious, you don't want to send your readers there for authoritative information on the subject.
You've got to consider the source and the purpose of your citation, but most of the time, you should read the whole thing. It's your reputation that's on the line, so it's best to make sure you understand your sources before you cite them.
You don't have to read the whole article if you're certain about the point it makes.
Ultimately it is up to you to defend your paper and if someone questions your findings you have to be able to give an appropriate answer. If they see that you misinterpreted something, because you didn't fully understand the article you cited they can call you out on that (regardless whether you skipped half of the article or just didn't understand it properly).
To add to the Hansen answer
Maybe you don't need to read an article completely, but abstract and conclusion are there to ease your way to understand an article and you must read them.
It also depends on the subject and your purpose of citation. For example if you claim about something, you should have read and understand it but if you cite to provide a context you can be less sensitive.
I don't think it's important to read the whole paper before citing it, unless you are extending on that paper's work.
Side note: A recent paper said that most of the citations are copied ("when a scientist writes a manuscript, he picks up several random recent papers, cites them and also copies some of their references").
Yes. Always read the whole article before citing. Don't be sloppy. Don't take lazy shortcuts. Write responsibly. This is academia, not second-rate journalism.
If you cite something you don't understand, or which is riddled with nonsense, or is later retracted, and you show no sign that you were aware of it in your citation, then it will reflect badly on you.
Obviously, in any paper you cite, there will be things that are relevant, and things that are not. But that doesn't mean you can avoid reading the paper, and only cherry-pick reading the one sentence in it that is convenient for you to build your argument. If you don't read it all, you won't know everything in it that's relevant.
Building comprehensively on predecessors' work is how scholarship progresses. Being lazy, omitting hte reading of your predecessors' work, and citing it blindly without reading it or understanding it, is how bad scholarship propagates.
If it's a large reference work such as a dictionary, then no, you aren't expected to read the whole thing: in such cases, you'll just have to get by with an appeal to authority, by using the most reputable dictionary you can.
