4) 讨论部分
总的要求：The author should tell the reader what the results mean by placing them in the context of previous published studies of the problem,即：与先有研究相比，本研究有何意义。
具体要求：
A． 简要说明研究背景（background）
B． 简要介绍总的发现（general findings）；
C． 介绍具体要点（introduction of points）
D． 与现有发现（若有）进行比较（comparison in the context of other studies）
E． 意义（suggested meaning）
F． 结论（conclusion）
G． 前瞻研究（future studies）
结论往往是论文中最长也是最难写的部分，主要原因是作者要对研究结果和发现进行分析、推断、演绎和推理，要求作者具有很强逻辑思维能力和英语文字组织能力。此外，这部分时态比较复杂，要分清实验过程和结果（过去时）与分析意见（确定：现在时；不确定或假设：过去时）的区别；他人研究结果（过去时或现在完成时）与本研究结果（过去时）的区别；普遍适用的结论（现在时）与只适用本研究的结论（过去时）的其别等。因此，对于however, may, might, could, would, possibly, probably, be likely to 等词（组）的使用以及we believe (think / consider) that, to our knowledge, in our experience (practice) 等插入语的使用就显得格外重要。
示例：
Parenteral nutrition is being used with increasing frequency as a primary source of caloric support in adult and pediatric patients with gastrointestinal problems. Numerous complications have been associated with the administration of TPN, including a significantly increased ncidence of gallbladder disease [3-5,7]. The data here suggest that cholecyste
ctomy is often required for the management of symptomatic gallbladder disease in this group of patients, and is associated with significant risks.[说明研究背景，包括意义] Of the 35 patients who required cholecystectomy for TPN-induced gallbladder disease, operative morbidity and mortality were 54 percent and 11 percent, respectively. Maingot [8] has stated that cholecystectomy “is one of the simplest and safest of the abdominal operations, and is ass
ociated with a low operative mortality rate (about 0.5 percent). A review of the pediatric literature suggests that when cholecystectomy is performed in children, the operative morbidity is less than 10 percent, and the mortality is less than 1 percent. [8,9] Glenn [11] has reported a mortality rate of less than 0.1 percent in over 5,000 patients under
the age of 50 years who underwent cholecystectomy. The morbidity and mortality observed in our group of receiving long-term TPN, therefore, were far in excess of what would be expected for a population of patients whose mean age was 29 years.
[提出本研究主要发现并将其与其他研究发现相比较]
Our data suggest that are specific factors unique to patients who require long-term TPN that contribute to the increased mortality and morbidity associated with cholecystectomy in this select group.[以下，作者用较大篇幅分析了这类病人死亡率和并发症增高的临床、实验室和手术等方面的原因，原文从略]
Based on the results of our studies, we believe that early cholecystectomy is indicated in patients with TPN-induced gallbladder disease. Obviously, all patients with symptomatic disease should undergo cholecystectomy unless there specific medical contraindications. These operations should be performed in a timely, elective fashion because delay may result in the need for urgent surgery and thereby, increase an already high risk. Although recent studies have suggested that cholecystectoy may not be warranted in otherwise healthy patients with asymptomatic gallbladder disease [20], we believe that this axiom does not apply to patie
nts with TPN-induced gallbladder disease. Out data suggest that the natural history of gallbladder disease in patients receiving TPN is considerably different from that of their counterparts not receiving TPN. Based on our findings, we recommend elective cholecystectomy in patients receiving TPN when gallstones first appear. Furthermore, cholecystectomy should be considered, especially in children without stones who are un
dergoing laparotomy for other reasons. [从对结果的分析及与其他研究的比较得出结论性意见，这是讨论部分最重要的内容 ] Whether TPN-induced gallstones can be prevented through daily stimulated gallbladder emptying awaits the results of further studies. [前瞻研究]
医学论文－正文写作详解
医学综述的撰写方法和步骤