“方法”部分应该使用过去时态,例如:“sections were stained with…” and “data were analyzedusing…”。但是在提及图表时应使用现在时,例如:“The patients’ clinical characteristics arelisted in Table 1”。 此外,当你在叙述某个事物的定义或当前对它公认的看法时也要用现在时,例如:“the cells weresubjected to hypoxia, which induces HIF-1expression…”。这句话中,虽然实验部分是用的过去时,但由于缺氧(hypoxia)导致HIF-1是一个普遍现象而不是限定于本文的结果,因此后面半句应该用现在时。
要列出所有试剂的供应商以及设备的厂家;有的期刊还要求列出其地址,即国家、州(如为美国)和市。叙述设备、试剂盒、试剂的时候应该用常用术语来具体描述,不要只用厂商的专门术语或只写型号。比如,不要写成:“Absorbance in each well was measured at a wavelength of 492 nm usinga Beckman Coulter AD 340C”,因为大多数人都对Beckman Coulter AD340C没有任何概念;应该写成:“Absorbance in each well was measured at a wavelengthof 492 nm using a multi-well plate reader (AD 340C, BeckmanCoulter)”,或者“Absorbance in each well was measured at a wavelength of492 nm using an AD 340C multi-well plate reader (Beckman Coulter Inc,Fullerton, CA, USA)”。
“…homogenates were spun at 10,000 × g and 4 °C for 12 min”这句话包含了时间、温度两个重要细节。而:“…homogenates were spun at 10,000 × g” 和更简化的 “homogenates were centrifuged” 两个句子中就遗漏这些细节。这些细节有可能对得到你的结果很重要,所以应该给出。
同理,不要只写:“Then, 10 μl of a propidium iodide solution was added to thecells”,因为这对读者毫无意义,除非他们知道该溶液的浓度。应该写成:“Propidium iodide was added to thewells to a final concentration of 0.5 μg/ml”。
下图节选自《The Journal of Clinical Investigation》所发表的一篇论文(doi:10.1172/JCI37155;经同意转载)的方法部分。它显示了“方法”部分的各种要素以及他们如何组合的。