Dr. Plopper’s Guide to Critical Reading of Primary Literature Overall tips: 总技巧
1. Just because a scientific study has been published, this does not mean it is perfect. And the imperfections are not so minute that a non-expert cannot find them. Any student of science can, and indeed should, read science critically. This means you can read a paper by a Nobel laureate and find fault with it. It is in fact expected that, as a practicing scientist, you can criticize any science. The level of your critical analysis will differ with your experience level, but you should be able to criticize science even as a relatively inexperienced undergraduate.
1、科学研究不能仅因为已发表，就认为它是完美的。它们的不足也不是微小到只有专业人员才能发现。任何从事科研的学生都能，而且确实应该能够，批判性地阅读科学文献。这意味着你读一篇诺贝尔奖获得者的文章都能在其中发现不足。它实际上期望作为科学工作者的你能对任何学科进行分析评论。你分析评论的水平会因你的经验水平而有差异，但你应该至少能够象一名相对无经验的本科生来分析科学文献。
2. Manuscripts are not read the same way newspapers or novels are read. One does not simply read every word, from the front to the back, in a single pass. The reason for this is fairly obvious: manuscripts contain a high density of information, and not all of this information is of equal value to the reader. In fact, quite a lot of effort is made by the authors and editors to break the information into discrete units that can
be read almost independently. Inexperienced readers of primary literature should pay close attention to how manuscripts are organized, and seek specific types of information from each section. You should read the manuscript many times, but each time read only a portion of it, and do so because you are looking for specific information.
2、科学原稿的阅读方式不能象读报纸和小说那样，不能简单地从送头到尾地阅读每个单词，而且只看一遍就行了。这个原因很明显：科学稿包含了高密度的信息，对读者来说，这些信息并不是等价的。实际上，作者和编辑花了很大气力来将信息分成独立的单元，这些单元几乎可以独立阅读。无经验的读者在阅读原始文献时应仔细留意文稿如何组织，寻每个部分的特别信息。你应该反复阅读文稿，但每次仅读其中的一部分，这样作的是因为你在寻特别的信息。
3. Have a good textbook handy to look up background information and definitions.
3、手边备本好的教科书来查背景知识和定义。
4. Reading a manuscript takes a lot of time, especially if you are unused to it. To do all of the procedures outlined here will take you at least three hours.
4、读一篇科学稿要花好多时间，特别是如果你从未接触过的知识。将以下纲领性的步骤作全就要花费至少三个小时。
Step-by-step method: 逐步顺序阅读
1. Read the Title. 读题
1a. Understand each word. The title provides the most important information in the manuscript. What, really, does this mean? This means the authors have combed through their data and have decided that if you remember nothing else about the paper, this is the one thing you should remember. You may be surprised to learn that most authors spend quite a lot of effort on the title, because they are forced to distil many months (or even years) of work into a single sentence. Imagine crunching an entire year of college courses into a single sentence! As a result, they shuffle and reshuffle their data until the most important point comes out. They also shuffle and reshuffle the words in the title.
1a.理解每个单词题目提供了原稿的最重要的信息。它真正的含义是什么？这意味着作者综合他们的资料，并决定如果这篇文章其它别的东西你记不住的话，这个是你应该记住的。你可能会对大部分作者在题目上花了很多气力感到吃惊，因为他们不得不将数月（甚至数年）的工作浓缩到一句话内。想象一下，将整整一年的课程咀嚼揉合成一句话多么困难！因此，他们将数据改组再改组，直到能够表现最重要的观点。同样，题目中的文字他们也是反复斟酌。
The result is that each word in a title usually carries a lot of weight. Because a lot of effort is put into cr
eating a title, it should be rich in information content. To the reader, this means you should be able to get a lot of ideas out of the title. I usually spend at least five (real) minutes thinking about the title before I read anything else; most beginning students spend about five seconds on a title, figuring, “If it’s important, I’ll learn about it later in the paper.” Bad idea!
结果当然是题目中的每个单词都常极有分量。因为花如此大的气力来确定题目，它理所当然地饱含着信息。对于读者来说，这意味着你应从题目中得出许多的想法。我通常花至少5分钟（真的）来在阅读其它内容前思考题目；大部分初学者用大约5秒钟的时间来读题目，估摸一下，“如果它很重要，我会在下面的文章中学习它。”馊主意！
1b. Create a list of experiments you expect to see in the paper. In practical terms, this means you should consider the implications of each word in a title. You should be able to derive a list of what sort of experiments you think the authors performed, what the data might have looked like, and how the authors reached their conclusions, before you even read the paper. Write this list down. It may be completely wrong, that’s OK. But try to think ahead about what will be coming. If eventually you discover that your list looks nothing like what the authors did, that is very instructional: did you miss a critical point, or (this happens) did they? Did they mislead you with their title? Many papers have titles that border on being advertisements: they paint the data in the most positive light, but may not be entir
ely accurate. Your job is to see through that! 1b、将你期望在文献中能看到的实验列表。从实践角度来说，这意味着你应该考虑过题目中每个单词的含义。甚至在你读论文前，你就应该能够由题目列出你觉得作者会作的实验清单，数据会是什么样子，作者怎样得出他们的结论。把这些清单记下来。它可能完全错误的，那没关系。但你在阅读全文之前就努力提
前思考过了。如果最终你发现你的实验清单与作者根本不一样，那非常有指导性了：我遗漏了关键点吗，或者是（有时确实是这样）作者遗漏了？他们的题目对你误导了吗？许多论文的题目近乎于广告：他们将数据涂上“阳性”的光彩，但这些数据却可能不是完全精确的。你的任务就是要识破它！
Example: Although not usually written as a declarative sentence, a title can be translated as such. Here is an example from a cell biology paper: “A Splice-Isoform of Vesicle-associated Membrane Protein-1 (VAMP-1) Contains a Mitochondrial Targeting Signal.” This sentence can be deconstructed easily: “X (verb) Y.” The verb “contains” is not overly scientific, but is has implications you should consider. The “X” in this case is rich in terms: “A Splice-Isoform of Vesicle-associated Membrane Protein-1…” When you read a title, make sure you understand what every single word means, or at least ask yourself how you could find out. In this case, if you don’t know what “splice isoform” means, go find out before you delve any deeper into the paper, because it must be a critical component of the whole manuscript (or it wouldn’t have made it into the title, right?). Usually a good place to find definitio
ns or explanations for especially obscure words is the Introduction section. Likewise the words “vesicle-associated,”“membrane,” and “protein.” These are all very common terms in cell biology, and you should have no trouble understanding them. After you get the meaning of each word down, string them together and determine what they mean collectively. In this case, it means, “A structurally altered form of a protein that binds to vesicles…” and that should conjure an image in your mind: what do vesicle associated proteins do? Don’t know? Go find out. What would make them interesting, especially if they were structurally altered? Any predictions? I’ll wager that you won’t predict that they have anything to do with mitochondria. Hmmm….
例子：虽然题目不通常用宣告的语句，但它能够转化为此类语句。这里是细胞生物学论文的一个例子：“囊泡相关膜蛋白-1的拼接同工型包含了线粒体目标信号。”这个句子能够简单分解为“动宾”结构。这个动词“含有”并不是彻头彻尾的科学词汇，但你应考虑它的含义。在这个例子里，“含有”这个动词密集于这些字眼：“囊泡相关膜蛋白-1的剪接同工型……”当你读题目时，确信你理解了每个单词的含义，或至少问自己你怎样到这些含义。这种情况下，如果你不知道什么是“剪接同工型”， (isoform:A protein having the same function and similar (or identical sequence), but the product of a different gene and usually tissue specific. Rather stronger in implication than homologous) 在进一步钻研论文前你去出它的含义，因为它肯定是整个原稿的关键组成（否则它就不会出现在题目中，对吗？）。通常寻含义
特别模糊的单词的定义和解释的好位置是引言部分。同理单词“囊泡相关”“膜”，和“蛋白质”的含义也要弄清。这些在细胞生物学里是非常普通的词，对它们的理解应该没有问题。当你写下每个单词的含义后，将它们串在一起，看它们合起来是什么含义。这个例子里，它表示“结合到囊泡上结构型上有改变的蛋白质……”它应该在你在意识中唤起这样的想象：囊泡关联蛋白质干啥？不知道？去寻答案。什么使他们有趣，特别是如果他们在结构上变化就更有趣了。有什么预言吗？我敢打赌你不会预言他们会与线粒体有关。嘿
嘿……
Do the same deconstruction to the “Y” term: what is a “mitochondrial targeting signal”? Where is it found? What does it do? Look it up if you don’t know.
同样对“宾语”进行解体：什么是“线粒体目标信号”？它在哪儿发现的？它的功能？如果你不知道，你要在教科书里查到。
Now combine the two ideas with the verb. The two apparently disparate ideas are actually related, according to this paper. How would you show that? Spend some time thinking hard about that. Any idea how someone might do it? If so, write it down. If not, put down the questions you’d need answered in order to come up with some experiments: “How do you show something is a splice variant?
” for example.
现在用动词把两个概念结合起来。根据这篇文章，两个明显分离的概念实际上是相关的。你如何来显示它们相关？花点时间努力思考一下，知道什么实验可以实现吗？如果有，将它写下来；如果没有，为了提出一些可能进行的实验，你可把需要回答的问题写下来，例如：“你是如何显示什么是一个剪接变异体？”
So, before proceeding, you should have a list: It either has a series of experiments you think might be done, or it has a set of questions that you need answers to in order to generate that list of experiments. Maybe it contains a few statements of each type. A big difference between an inexperienced and an experienced researcher is how easily they can draw up this list of experiments. You should be striving to do this as quickly and thoroughly as possible. And remember: having a list that varies from the list of actual experiments done by the authors is perfectly OK.
所以，在开始前，你应有个清单：它要么是一系列你认为可行的实验，要么是为了列出实验清单你所需要回答的一系列问题。也许它包含了每一类型的陈述。无经验和有经验的研究者间很大的差别是他们草拟实验清单的难易之分。你应该努力尽可能快而全面地作到这点。记住：如果清单和实际作者所做的实验清单有分别是最好的。
If you need to look in the paper to find the answers to your list of questions, do that next. Look at the data/figures, and check the Materials and Methods for the “how to” portion of addressing your question. Read these sections only for that information! Do not get bogged down in minute details: know what you are looking for, and find it. Skip/ignore anything that doesn’t answer your questions. Then, generate your list of experiments.
如果你需要查论文来寻你实验清单的答案，下一步再做。看看资料/图，检查材料和方法来寻“如何”划分你提出的问题。阅读这些部分仅仅为获得这些信息！不要陷入太细微末节的细节：知道你寻什么，到它。跳过/略过不能回答你问题的内容。然后，列出你的实验清单。
Do not read any more of the paper until you get this list together. I usually just abbreviate it in the margin of the first page. At this point all you have read is the
title (plus maybe you’ve skimmed the rest), yet you have a good handle on what the paper should be about, and even a set of expectations to bring with you as you delve into the meat of the paper. This will help considerably when trying to decide what else in the paper really matters: Sometimes the pH of a buffer is boring, sometimes it is crucial.
只有把这些清单收集起来，你才能继续读论文的其它部分。我通常仅在首页的空白处简要地列出清单。
这个点上你所读的可能只有题目（加上你可能略过了其它部分），然而你对该文应该与哪些相关已有了一些掌握，甚至在你准备钻研论文实质时，你已有了一整套期望。当试图决定论文中别的哪些内容真正相关时，这会有很大的帮助：有时缓冲液的pH很枯燥，有时却是至关重要。
Given the list, now you can test your ideas by reading the rest of the paper to find out what experiments they actually did. How and where do you find that? In the Results section.sort of order
清单已列出，现在你能够通过阅读论文的其余部分来出作者实际上作了什么实验来检验自己的想法了。你怎样，在哪可到这些？有结果部分。
But before we go there, let’s get a preview by reading a summary of the results in the abstract.
但在我们开始之前，让我们通过阅读摘要中的结果概括对此预先了解。
2. Read the Abstract. 阅读摘要
The abstract is a summary of the whole paper. It usually contains a condensed introduction (1-2 sentences) explaining the rationale for the work. Then a brief summary of the data, with slight reference to the experimental methods at best. Finally, a concluding sentence, perhaps with mention of the implications of the work.
摘要是全文的概括，它通常包含有浓缩性的引言，解释实验的基本原理。然后简短的数据概括，最好稍稍提及实验方法。最后是结论句，也许还有该论著的含义。
Like the title, the abstract is a dense piece of writing. You can get lots of info here, but this time you are looking only for hints as to how and why the experiments were performed. You can then tell how close your list is to theirs. Don’t rewrite your list! Just get it in your head that your experiments and theirs are either similar or not. You will also get a sense for the order in which experiments are going to be presented. Ignore everything else.
与题目相似，摘要是论文的浓缩。你能从中获得很多信息，但这次你要寻的仅是进行实验的方法和原因的提示。然后你就知道你的清单与他们的相近程度。不要重写你的清单！仅记住你的实验和他们相近或不同。你也会察觉到诸多实验以何种顺序列出。其它的一概忽略。
3. Read the Results section. 读结果部分
3a. Read the text of the results without critiquing the data. Go slowly and carefully here. Since this is your first pass through the data, do not try to take it