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。）