学术著作中不注明信息来源的行为叫做抄袭，这是一种学术不端行为，应努力避免。互联网上的信息也必须注明来源。很多情况下，较好的做法是在使用某个图表或某段文字之前获得网站所有者的同意。

　　被公认为常识的事实不需注明出处，例如：A vast number of endemic species exists on the Galapagos Islands.　但是，不被周知的信息和用来解释事实的想法需要注明出处，如：Based on a recent study, the blue iguanas of the Grand Cayman Islands are an endangered species (9). （“blue iguanas of the Grand Cayman Islands are an endangered species” 这个发现不是一个事实而是一种解释。因此，需要注明出处。）

试比较：

　　Because nitrogen (N) is an essential component of proteins, enzymes, and other biologically important compounds, the natural cycling of N in freshwater ecosystems needs to be studied in detail. （不需注明出处的常识性引用）// While low nitrogen (N) availability can limit primary productivity, excess N has been linked to eutrophication and health concerns (19). （需要注明出处的他人研究成果）

　　Historical eruptions are almost always preceded and accompanied by “volcanic unrest,” providing early warning of a possible impending eruption. （不需注明出处的常识性引用）//The eruption of Mount Pinatubo in 1991 was preceded by a relatively short progression of precursory activity before its full-blown eruption (22). （需要注明出处的他人研究成果）

　　学术引用中的改写可能是写作中吸收他人研究成果时用得最多的技能。改写是自己的语言表达出他人的思想，只替换原文的一两个词或只改变原句的结构不是改写而是抄袭。在科技写作中，避免抄袭的最好方法是在收集和使用信息时做到几下几点：

（1）记录下每一条有可能需要引用的内容，并详细记录文献来源（可借助Endnote或Reference Manager）。

（2）记笔记的时候把书合上，用自己的语言描述书中的思想。

（3）如果摘抄原文，需使用引号（直接引用在科技写作中并不多见）。

（4）引用时必须用自己的语言表述原文中的某些细节，并核对文献以确保和引用的表述正确无误。

比较以下各段（例1）：

　　原文：Healthy older adults often experience mild decline in some areas of cognition. The most prominent cognitive deficits of normal aging include forgetfulness, vulnerability to distraction and other types of interference, as well as impairments in multi-tasking and mental flexibility. These cognitive functions are the domain of the prefrontal cortex, the most highly evolved part of the human brain. Prefrontal cortical cognitive abilities begin to weaken even in middle age, and are especially impaired when we are stressed. Understanding how the prefrontal cortex changes with age is a top priority for rescuing the memory and attention functions we need to survive in our fast-paced, complex culture.

　　构成抄袭的段落: In healthy older adults often some areas’ of cognition decline. The most noticeable cognitive declines of normal aging include forgetfulness, vulnerability to distraction, and problems in multi-tasking. These cognitive tasks are localized in the prefrontal cortex, which is the most highly evolved portion of the brain. Already in middle age prefrontal cortical cognitive functions start to decrease. Such functions are also particularly affected during any type of stress. Studying memory and attention is important to understand how the prefrontal cortex changes with age. It is particularly important to understand these changes in our current fast-paced life style.（作者只改动了原文的几个词和短语，或改变了原句的顺序；并且未注明任何思想或事实的出处。）

　　改写后的段落:A recent study shows that the process of aging is accompanied by a decline in cognitive abilities, deficits in cognitive abilities, deficits in working memory, and compromised integrity of neural circuitry in the brain (3). Impairments in these executive operations compromise the regulation of thought, emotion, and behavior, and ultimately jeopardize independence and quality of life. Elucidating mechanisms underlying the decline of neural circuitry is critical for the treatment of debilitating cognitive deficits, such as those found in the elderly.（作者用自己的语言准确地转述了原文的信息，并且告知读者信息的来源。）

比较以下各段（例2）：

　　原文: It has currently been recognized that both the type and characteristics of the rust layers formed on the steel surfaces are very important because they can determine their protective properties. According to a recent theoretical model developed by Hoerlé et al. (2), the long-term corrosion behavior of iron exposed to wet-dry cycles is largely controlled by the characteristics of the rust layers. Additionally, the differences between the corrosion behavior observed for different types of steels have been related to the rust layer characteristics. Okada et al. (8) have carefully investigated, by using detailed variable temperature Mössbauer spectrometry, the protective rust formed on both weathering and mild steels after 35 years of exposure to a Japanese semirural type atmosphere. They reported that the rust on both steels it composed of goethite (major component), lepidocrocite (minor component) and traces of magnetite.

　　构成抄袭的段落: Both the type and characteristics of the layers formed on the steel surfaces are very important because they determine their protective properties. Recently, Hoerlé et al. developed a theoretical model (2) that the long-term corrosion by the characteristics of the rust layers. The differences between the corrosion behavior observed for different types of steels have also been related to the rust layer characteristics. Using detailed variable temperature Mössbauer spectrometry, the protective rust formed on both weathering and mild steels after 35 years of exposure to a Japanese semirural type atmosphere have been determined by Okada et al. (8) who reported that the rust on both steels is composed of goethite (major component), lepidocrocite(minor component) and traces of magnetite.（尽管作者注明了出处，但因其只改动了几个词和短语，仍然构成抄袭。）

　　改写后的段落: Rust constituents can determine the performance of steels and influence their life expectancy. The characteristics of the rust layers control the long term corrosion behavior of iron exposed to wet-dry cycles (2). For example, after 35 years of exposure in Japan, rust formed on steels under various conditions is composed of mainly goethite, some lepidocrocite, and traces of magnetite(8).（可接受的改写版本。）

　　与研究论文的其他部分不同，许多文章的材料与方法部分都极其相似，这主要是因为描述这些除了变量不同，技术和体系基本上相同的方法就只有那么几个。对于写作类似这样的材料与方法部分的段落，参考收集其他文章此部分的范例用语不失为一个好办法。但不宜大篇幅地摘抄，可适当借用单个的范例短语和表达方式。

比较以下各段（例3）：

　　论文A的方法描述: Real-time fluorescence quantitative PR was performed in an Applied Biosystems Prism 7000 instrument in the reactions containing an Applied Biosystems SYBR green master mix reagent and oligonucleotide pairs to the endogenous control gene ‘A’ and cDNA of ‘B’. The reagents were denatured of 95 °Cfor 10 min, followed by 40 cycles of 15s at 95℃ and 60s at 60 °C. The primer sequences (5’-3’) were ‘A’ reverse, 5’-GACAC….

　　论文B的方法描述: PCR amplification of ‘X’ sequences was done using the GC RICH PCR System (Roche, Mannheim, Germany). All non-‘X’ sequences were amplified using Taq DNA polymerase (Promega, Madison,WI). Primers were designed using published sequences for ‘X-I’ (GenBank: Xxxxxx) and ‘x-13’ (GenBank: Xxxxxx) (Table 1). PCR thermal cycling conditions were: 2 min at 50 °C, 10 min at 95 °C, followed by 40 cycles of 15s at 95 °C and 1 min at 60 °C. PCR reactions were run with molecular weight standards on 0.8% agarose gels containing ethidium bromide and visualized by UV light. The primers used were: 5’-GGCTC….

　　论文C的方法描述: Real-time PCR were performed using the TaKaRa SYBR PCR kit and ABI Prism 7000 sequence detection system according to the manufacturer’s specifications. The primers for amplification were abc…and 5’-GACAC… and def (5’-GCATC… and 5’-GACT…). Total reaction volume was 50 ml in including 25 ml SYBR premix Ex Taq with SYBR Green I, 300 nM forward and reverse primers and 2 ml cDNA. The thermal cycler program was 1 cycle at 95 °C for 10 s, followed by 40 cycles at 95 °C for 5s and 60 °C for 30 s. The PCR products were detected by electrophoresis through a 2% agarose gel stained with ethidium bromide.