从文献实例角度讲解sci注意要点。一篇，有很多类型，原始研究、、信件、述评、系统评价等等。不同的类型，写作要求也是不同的。今天小编基于一篇，从实例的角度讲述几个sci中需要注意的几个问题。
题目：不可过长，不可过短，体现关键词，夺人眼球
heparinversusenoxaparin for prevention of venousthromboembolism after trauma: arandomized noninferioritytrial (注意红色字体)
摘要：结构式摘要、简短扼要、概括总结
background:research comparing enoxaparin with unfractionated heparin (ufh) given every 12 hours for venous thromboembolism (vte)prophylaxis after trauma overlooks original recommendations that ufh be given every 8 hours. we conducted a prospective,randomized, noninferiority trial comparing ufh every 8 hours and standard enoxaparin every 12 hours.we hypothesizedthat the incidence of vte in trauma patients receiving ufh every 8 hours would be no more than 10% higher than that in patients receiving enoxaparin every 12 hours.(表达目的)
methods:trauma patients who met criteria for vte prophylaxis at a level i trauma center were randomly assigned to 5,000-u ufhevery 8 hours or 30-mg enoxaparin every 12 hours between november 2012 and september 2014. surveillance duplex ul-trasound was performed twice weekly on intensive care unit patients and weekly on ward patients. primary end points were deep vein thrombosis diagnosed by duplex ultrasound and pulmonary embolism diagnosed by computed tomography angiography.(where,who,what)
results:of 495 randomized patients, 220 received ufh and 216 received enoxaparin for analysis. overall, 105 in the ufh group and103 in the enoxaparin group underwent vte surveillance or diagnostic testing. in the analysis of randomized patients who received treatment, ufh was noninferior compared with enoxaparin (absolute vte risk difference, 3.1%; 95% confidence interval, j1.6% to 7.7%; p = 0.196); however, in the screening ultrasound group, the noninferiority of ufh was inconclusive(absolute vte risk difference, 6.5%; 95% confidence interval, j2.9% to 15.8%; p = 0.179). the two treatments did not differ with regard to adverse events. the pharmaceutical cost for the regimen of ufh ($2,809) was nearly 20-fold lower than that for enoxaparin ($54,138).(体现主要结果，不可只写p值)
conclusion:a regimen of ufh every 8 hours may be noninferior to enoxaparin every 12 hours for the prevention of vte following trauma.given ufh’s cost advantage, the use of ufh for vte prophylaxis may offer greater value. (j trauma acute care surg.2015;79: 961y969. 凯发天生赢家一触即发官网 copyright * 2015 wolters kluwer health, inc. all rights reserved.)(一定是结果的总结)
introducation
从大到小，提出问题：就是从大方面描述(流行病)到具体问题的描述(某个疾病)，最后提出自己研究的目的。
正如上例，在introducation中首先讲述了vte在创伤患者中的流行病，然后讲了现在预防的主流方法，最后提出目前方案的局限性映衬出自己研究的目的。作者是这样提出问题的：we hypothesized that the incidence of vte in trauma patients receiving ufh every 8 hours would be no more than 10% higher (i.e., noninferior) than that in patients receiving enoxaparin every 12 hours.
methods
方法：pico，统计，。pico是什么？picos是participants（研究对象），intervention（干预），control（对照），outcome（结局），study design（研究设计）的缩写，其实最早以前只有pico，后来才加了个s。不同规范对picos的内涵解释略有出入，但总的来说，其目的只有一个，就是通过picos这几个维度，把“临床问题”这个不容易被定位的问题，用标准化的方法表述出来。我们看看这篇文章是什么体现pico的：
p：patients 18 years and older and at risk forvte based on the american college of chest physicians guidelines were included. 14 those with an estimated injury severity score (iss) equal to or less than 9, those expected to have a hospital length of stay less than 7 days by reason of discharge or death, and prisoners were excluded. additional exclusion criteria included international normalized ratio of 1.2 or greater, body mass index (bmi) greater than 40, creatinine of 1.3 or greater, transfer time to our facility greater than 24 hours, and pregnancy.
i：eligible patients was randomized to receive either 5,000 u of ufh every 8 hours
c：or30 mg of enoxaparin every 12 hours.
o：primary end pointswere a new dvt or progression of a known below-knee dvt diagnosed by venous duplex ultra- sound (u/s) and a pe diagnosed by computed tomography angiography.secondary end pointsincluded bleeding events and the occurrence of heparin-induced thrombocytopenia (hit).(对于如何判断这些主次要结果都进行了详细描述，可重复性非常好)
s：a prospective, randomized, two-arm, noninferiority trial(研究类型)
统计：统计方面，其实是非常固定的，如果你没有采用非常高级的统计学方法。则可以多看一些文献，按照套路出牌即可。根据数据类型(分类/连续)，分布情况(正态/非正态)选择合适的描述统计和统计推断的方法。
：任何统计推断都是在一定的基础上进行的。现在大部分杂志对于rct研究都要求写明如何计算的。本文作者写道：to achieve 90% power using an a priori margin of 10% with a one-sided > of 0.025, a total of 182 patients (91 in each arm) was required。
results
在结果描述中，需要注意的是需要和方法中的相对应。在方法中描述了几个结局指标，在结果中都要提到，至少是不能少的。通常的顺序是：纳入人群的基本信息，分组情况，主要结局指标，次要结局指标，事后分析。在结果中就难免会有图表。需要注意的一点就是图表的内容尽量不要和文字部分充分。另外需要注意的就是表头和图例的书写，一定要简明扼要，吸引眼球，因为现在搜索文献基本通过，检索出来之后首先看到的就是题目摘要，之后如果有全文下载下来，一般就是看看摘要，图表，而这时如果你的表头和图例写的很好，就很容易使读者理解这篇文献的意识。另外在表头和图例中尽量少用简写。
discussion
讨论部分的撰写一篇论文中最为困难的，也是一篇文献的精髓，其实可以理解为一篇小型的。那要怎么写，也是有套路的，通常来说是先写自己的主要发现，不要单纯的描述结果，对主要结果进行提炼，然后写一些自己研究结果和之前文献的差异，当然可以按照主次要结果分开描述，然后不要忘记提出未来研究的方向和研究的局限性。看看这篇文献是怎么写的：
we sought to determine whether a regimen of ufh every8 hours was inferior to standard enoxaparin every 12 hours forvte prophylaxis in trauma patients, as similar effectivenesswould provide a cost-savings rationale favoring the use ofufh. in the analysis of the randomized treated sample, wefound ufh every 8 hours was noninferior to enoxaparin basedon an a priori 10% noninferiority margin with an absolutedifference in vte rates of 3% between treatment groups. although the two treatments did not differ with regard to adverseevents, the pharmaceutical cost of the ufh regimen was nearly。。。。。对结果进行描述
other studies in diverse patient groups reveal that ufhdelivered every 8 hours is an effective vte prophylaxis. in1974, evaluating two different regimens of ufh (5,000 u) ingeneral surgery patients, corrigan et al. 9 found the regimen ofevery 8 hours superior to dosing every 12 hours for the pre-vention of total dvts as well as above-knee dvts.。。。。。。in contrast, results of a recent prospective economicevaluationby fowleretal。。。。。。(和之前文献进行比较)
thus, the most cost-effective vtechemoprophylaxis in the future may focus on nonheparinoidagents that are more effective in trauma patients. (指出未来研究方向)
our study has several limitations. (局限性)
conclusion
a regimen of ufh every 8 hours may be noninferior to enoxaparin every 12 hours for the prevention of vte following trauma.given ufh’s cost advantage, the use of ufh for vte prophylaxis may offer greater value.
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