例谈留学生dissertation中的引言写作（医学专业）
11-20, 2017
引言（Introduction）是dissertation开头部分，也是较为难写的部分。特别是对于留学生而言，往往把更多的时间放到对正文主体的布局或者格式的调整，在引言上并不会下太多功夫，影响dissertation的质量。引言在留学生dissertation中是非常重要的，一个好的引言可以让读者迅速把握与文章相关的研究背景以及本次研究的目的，从而吸引读者阅读全文，进一步深入了解研究细节。本文通过对优秀范文进行分析，对医学dissertation的引言写作思路与方法进行详细介绍，希望对留学生有所帮助。
一般来说，引言包含以下内容：
简单介绍相关背景；
说明研究现状以及仍然存在的未解问题；
引出本研究，阐明研究的目的和使用的方法，必要的时候简单介绍研究的发现和意义；
在介绍背景和研究现状的时候要简要地引用相关文献来指引读者。
有时，我们也可以把引言的写作思路形象的理解成一个由远及近、由大而小或由面到点的过程。
以下引言来自dissertation“Stable High-Sensitivity Cardiac Troponin T Levels and Outcomes in Patients With Chest Pain”
DOI: 10.1016/j.jacc.2017.08.064
J Am Coll Cardiol 2017; 70: 2226–36
我们通过这个例子来体会一下引言的写作思路和常用的英文表达。
High-sensitivity cardiac troponin (hs-cTn) assays have been established as key cardiac biomarkers for the diagnosis of myocardial infarction (MI) (1). The improved early diagnostic features have led to earlier rule-out and rule-in of MI in the emergency department (ED) (2–6).
本次研究和hs-cTn相关，所以先简单介绍一下关于hs-cTn的临床应用和意义，属于背景介绍，让读者对hs-cTn有一个基本的了解。
可借鉴的英文表达
... established as key cardiac biomarkers ... 表示已经被确立为一种心脏生物标志物，相当于widely used as。
Although older-generation troponin assays offered useful prognostic information in patients with cardiac disease (7–9), evidence is consistent that the newer high-sensitivity assays retain prognostic value at levels that were undetectable with the older assays (10,11).
对hs-cTn的临床应用进一步说明，提到newer high-sensitivity assays的敏感性更高，对于older assays不能检测到的hs-cTn量都能检测到，且仍具有预后价值，从而顺利过渡到下面的内容。#p#分页标题#e#
可借鉴的英文表达
evidence is consistent that ... 表示相关文献的结论一致。
... at levels that were undetectable with the older assays ... 相当于cannot be detected with the older assays，with可以替换成by或using。
The increased sensitivity has been associated with decreased specificity, causing a substantial proportion of patients without MI to have hs-cTn levels above the 99th percentile value, which is the cutoff level for the diagnosis of MI (12,13). As for patients with cardiac disease, troponin levels have been found to be independent determinants and predictors of adverse outcomes in patients with noncardiac acute medical conditions (14).
虽然敏感性提高了，但特异性下降，很多hs-cTn检测水平高的患者未必是心肌梗死，hs-cTn对非心脏类疾病也有预后价值。
可借鉴的英文表达
The increased sensitivity has been associated with decreased specificity, causing ... 敏感性提高伴随着特异性下降 ；associated with常表示二者的出现有一定的关联性，比如二者之间存在因果关系或有共同的原因，而correlated with常表示二者的变化有一定的关联性，比如正相关、负相关。 使用动名词引导补语值得借鉴，可以使句式更加丰富，增加句子的层次感。
Investigation and treatment of these patients are focused on the underlying conditions associated with elevated hs-cTn levels. Persistently elevated hs-cTn levels without a typical rise and/or fall pattern indicate chronic myocardial injury.
本次研究讨论的不光是hs-cTn levels，而且是stable hs-cTn levels，所以，从这里开始就出现 persistently elevated hs-cTn levels without a typical rise and/or fall pattern了。
可借鉴的英文表达
... the underlying conditions associated with elevated hs-cTn levels underlying和associated with搭配的这种表达形式可以借用，比如underlying mechanism associated with，表示现象背后的原因。
Knowledge on how to investigate or treat these patients to prevent future adverse outcomes is limited (15). Moreover, in patients with chest pain but no MI, or any other condition that may affect troponin levels acutely, few data are available on the association between the high-sensitivity cardiac troponin T (hs-cTnT) level and long-term outcomes.
由远及近，开始进入本次研究的范畴了。 limited和few这些词点明了目前相关研究的不足，从而体现出本次研究的必要性。#p#分页标题#e#
可借鉴的英文表达
few data are available on ... 摘要部分作者用的是There is a paucity of data on ... 这一表达，意思都是一样的，类似表达大家更容易想到用there be句型，其实available也可以用，可以增加表达的丰富性。这个表达可以用来说明目前相关研究的不足，体现出本次研究的必要性。
Therefore, we conducted a large observational cohort study including all consecutive patients who sought medical attention for chest pain during a 4-year period at our hospital to investigate the association between stable hs-cTnT levels and long-term outcomes.
正式介绍本次研究的目的，即to investigate the association between stable hs-cTnT levels and long-term outcomes (in patients with chest pain) ，以及本次研究使用的方法，即a large observational cohort study。
可借鉴的英文表达
consecutive patients 连续患者，即在某个时间段内将所有就诊患者入选研究，这是一种降低选择偏倚的方法。
sought medical attention 就诊的一种表达，可以借鉴。
关于文献引用：在这个并不长的引言中，作者积极引用文献，文献数目达到15条，起到了较好的引导作用。要写好一篇dissertation，尤其是引言和讨论部分，需要我们留学生充分阅读相关文献，然后将最有用的内容提炼出来加入到文章中。
一般来说，引言包含以下内容：
简单介绍相关背景；
说明研究现状以及仍然存在的未解问题；
引出本研究，阐明研究的目的和使用的方法，必要的时候简单介绍研究的发现和意义；
在介绍背景和研究现状的时候要简要地引用相关文献来指引读者。
有时，我们也可以把引言的写作思路形象的理解成一个由远及近、由大而小或由面到点的过程。
以下引言来自dissertation“Stable High-Sensitivity Cardiac Troponin T Levels and Outcomes in Patients With Chest Pain”
DOI: 10.1016/j.jacc.2017.08.064
J Am Coll Cardiol 2017; 70: 2226–36
我们通过这个例子来体会一下引言的写作思路和常用的英文表达。
High-sensitivity cardiac troponin (hs-cTn) assays have been established as key cardiac biomarkers for the diagnosis of myocardial infarction (MI) (1). The improved early diagnostic features have led to earlier rule-out and rule-in of MI in the emergency department (ED) (2–6).
本次研究和hs-cTn相关，所以先简单介绍一下关于hs-cTn的临床应用和意义，属于背景介绍，让读者对hs-cTn有一个基本的了解。
可借鉴的英文表达
... established as key cardiac biomarkers ... 表示已经被确立为一种心脏生物标志物，相当于widely used as。
Although older-generation troponin assays offered useful prognostic information in patients with cardiac disease (7–9), evidence is consistent that the newer high-sensitivity assays retain prognostic value at levels that were undetectable with the older assays (10,11).
对hs-cTn的临床应用进一步说明，提到newer high-sensitivity assays的敏感性更高，对于older assays不能检测到的hs-cTn量都能检测到，且仍具有预后价值，从而顺利过渡到下面的内容。#p#分页标题#e#
可借鉴的英文表达
evidence is consistent that ... 表示相关文献的结论一致。
... at levels that were undetectable with the older assays ... 相当于cannot be detected with the older assays，with可以替换成by或using。
The increased sensitivity has been associated with decreased specificity, causing a substantial proportion of patients without MI to have hs-cTn levels above the 99th percentile value, which is the cutoff level for the diagnosis of MI (12,13). As for patients with cardiac disease, troponin levels have been found to be independent determinants and predictors of adverse outcomes in patients with noncardiac acute medical conditions (14).
虽然敏感性提高了，但特异性下降，很多hs-cTn检测水平高的患者未必是心肌梗死，hs-cTn对非心脏类疾病也有预后价值。
可借鉴的英文表达
The increased sensitivity has been associated with decreased specificity, causing ... 敏感性提高伴随着特异性下降 ；associated with常表示二者的出现有一定的关联性，比如二者之间存在因果关系或有共同的原因，而correlated with常表示二者的变化有一定的关联性，比如正相关、负相关。 使用动名词引导补语值得借鉴，可以使句式更加丰富，增加句子的层次感。
Investigation and treatment of these patients are focused on the underlying conditions associated with elevated hs-cTn levels. Persistently elevated hs-cTn levels without a typical rise and/or fall pattern indicate chronic myocardial injury.
本次研究讨论的不光是hs-cTn levels，而且是stable hs-cTn levels，所以，从这里开始就出现 persistently elevated hs-cTn levels without a typical rise and/or fall pattern了。
可借鉴的英文表达
... the underlying conditions associated with elevated hs-cTn levels underlying和associated with搭配的这种表达形式可以借用，比如underlying mechanism associated with，表示现象背后的原因。
Knowledge on how to investigate or treat these patients to prevent future adverse outcomes is limited (15). Moreover, in patients with chest pain but no MI, or any other condition that may affect troponin levels acutely, few data are available on the association between the high-sensitivity cardiac troponin T (hs-cTnT) level and long-term outcomes.
由远及近，开始进入本次研究的范畴了。 limited和few这些词点明了目前相关研究的不足，从而体现出本次研究的必要性。#p#分页标题#e#
可借鉴的英文表达
few data are available on ... 摘要部分作者用的是There is a paucity of data on ... 这一表达，意思都是一样的，类似表达大家更容易想到用there be句型，其实available也可以用，可以增加表达的丰富性。这个表达可以用来说明目前相关研究的不足，体现出本次研究的必要性。
Therefore, we conducted a large observational cohort study including all consecutive patients who sought medical attention for chest pain during a 4-year period at our hospital to investigate the association between stable hs-cTnT levels and long-term outcomes.
正式介绍本次研究的目的，即to investigate the association between stable hs-cTnT levels and long-term outcomes (in patients with chest pain) ，以及本次研究使用的方法，即a large observational cohort study。
可借鉴的英文表达
consecutive patients 连续患者，即在某个时间段内将所有就诊患者入选研究，这是一种降低选择偏倚的方法。
sought medical attention 就诊的一种表达，可以借鉴。
关于文献引用：在这个并不长的引言中，作者积极引用文献，文献数目达到15条，起到了较好的引导作用。要写好一篇dissertation，尤其是引言和讨论部分，需要我们留学生充分阅读相关文献，然后将最有用的内容提炼出来加入到文章中。
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