全文获取类型
收费全文 | 531篇 |
免费 | 71篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 2篇 |
综合类 | 22篇 |
化学工业 | 261篇 |
金属工艺 | 5篇 |
机械仪表 | 6篇 |
建筑科学 | 6篇 |
矿业工程 | 1篇 |
能源动力 | 6篇 |
轻工业 | 144篇 |
水利工程 | 1篇 |
石油天然气 | 5篇 |
无线电 | 100篇 |
一般工业技术 | 33篇 |
冶金工业 | 5篇 |
原子能技术 | 5篇 |
自动化技术 | 13篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 16篇 |
2021年 | 24篇 |
2020年 | 22篇 |
2019年 | 11篇 |
2018年 | 12篇 |
2017年 | 17篇 |
2016年 | 25篇 |
2015年 | 19篇 |
2014年 | 29篇 |
2013年 | 20篇 |
2012年 | 39篇 |
2011年 | 30篇 |
2010年 | 20篇 |
2009年 | 20篇 |
2008年 | 44篇 |
2007年 | 33篇 |
2006年 | 47篇 |
2005年 | 30篇 |
2004年 | 23篇 |
2003年 | 19篇 |
2002年 | 21篇 |
2001年 | 21篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1951年 | 2篇 |
排序方式: 共有615条查询结果,搜索用时 0 毫秒
101.
从核酸探针、聚合酶链式反应、分子标记、实时PCR等分子生物学技术在双歧杆菌检测中的应用等方面作以综述,并指出各种检测技术的局限性及应用前景。 相似文献
102.
103.
104.
食品中所含的无机元素,对人体的营养健康和摄入安全有至关重要的作用,研究和分析食品中的无机元素,有利于评价食品的营养价值,规避有毒有害食品;了解食品被污染的情况和程度,以便查清和控制污染源;也有利于指导营养强化食品的生产和开发及食品加工工艺的改进和食品质量的提高。因此,在食品生产过程都需要对无机元素含量进行监控和检测。本文综述了目前国内外食品中无机元素分析的主要方法及其特点和质量控制水平,既包含了传统的化学法、物理法,也涵盖了近些年才兴起的纳米技术法、生物技术法等,并列举了这些分析检测方法在近年来的实际应用,阐明了食品中无机元素分析方法的研究发展趋势,旨在为食品中无机元素分析检测研究者和从业者提供一定参考。 相似文献
105.
We assessed the potential public health impacts of foods derived from recombinant DNA technology that have been modified to have improved nutrient profiles using omega-3-enhanced vegetable oils as an example. Other examples of crops in development include canola plants with increased vitamin C and rice with higher levels of beta-carotene. The change in consumption of omega-3 fatty acids if vegetable oils were replaced with stearidonic acid-enhanced versions was estimated. The results showed that stearidonic acid and gamma-linolenic acid consumption would increase by 5.43 g/d for males and 4.14 g/d for females. The increase in stearidonic acid in eicosapentaenoic acid equivalents was 1.63 g/d for males and 1.24 g/d for females. 相似文献
106.
《Food Reviews International》2013,29(4):437-473
Abstract Food irradiation is one of the most extensively and thoroughly studied methods of food preservation. Despite voluminous data on safety and wholesomeness of irradiated foods, food irradiation is still a “process in waiting.” Although some countries are allowing the use of irradiation technology on certain foods, its full potential is not recognized. Only 37 countries worldwide permit the use of this technology. If used to its full potential, food irradiation can save millions of human lives being lost annually due to food‐borne diseases or starvation and can add billions of dollars to the world economy. This paper briefly reviews the history and chemistry of food irradiation along with its main applications, impediments to its adoption, and its role in improving food availability and health situation, particularly in developing countries of the world. 相似文献
107.
Daniel R. Masys 《Journal of research of the National Institute of Standards and Technology》1989,94(1):59-63
Two decades have passed since the first large scale, public access computer-based information systems were developed to store and disseminate the knowledge of medicine and biology. These first systems were bibliographic, and though the searching of computer files of citations remains the most common use of biological databases, there are dramatic forces at work in basic biology which are driving a transition from the printed page to the factual database. Unlike bibliographic systems, which contain only a pointer to information located elsewhere, factual data-bases contain the information sought. Development of automated methods to sequence DNA, RNA, proteins, and other macromolecules have yielded oceans of cryptic symbols, for which there is an absolute dependence upon computerized factual databases to acquire, store, retrieve, and analyze data. The Human Genome Project has focussed attention on the information science aspects of nucleic acid data, yet for the practicing scientist nucleic acids and other sequence data are just one piece of an increasingly complex biological puzzle whose solution will be expressed in terms of structure and function. Access to and integration of information across multiple related biological data-bases is a major challenge facing information system builders, a challenge which holds the promise of creating knowledge synergy from what are today disconnected, stand-alone information sources. 相似文献
108.
C. J. KIRBY B. E. BROOKER B. A. LAW 《International Journal of Food Science & Technology》1987,22(4):355-375
Improved efficiency of liposome encapsulation of a cheese-ripening enzyme and increased retention of encapsulated enzyme by cheese curd are reported. The economy of enzyme usage for accelerating the rate of ripening of Cheddar cheese has been improved about 100-fold over previously reported methods. This has made feasible the use of microencapsulated enzymes for large-scale cheese production. Objective measurement of cheese ripening by proteolytic indices, and subjective evaluation of flavour quality and intensity by trained taste panels, indicate that cheeses are ripened by the microencapsulated enzyme in half the normal time. Investigations aimed at further improving the efficiency and commercial feasibility of the process are reported, and the possibility of using this technology for other aspects of food processing are discussed. 相似文献
109.
Biotechnology represents the newest challenge in the ongoing scientific progress in this millennium. Indeed what were seen as promising technologies a few years ago have already produced results; new crop varieties, animal species and agricultural processes. In crop improvement, for example, biotechnology has produced a wide range of applications including micro-propagation of crop varieties for commercial purposes, somatic embryogenesis, inter-specific crosses, gene transfers, and disease control and haploid production. Although modest in comparison with the prospects originally envisaged, mankind cannot but acknowledge these achievements, the regulatory control and commercial exploitation of biotechnology on standards of living of the human society. 相似文献
110.
食品化工生物技术的现状与展望 总被引:4,自引:0,他引:4
介绍了酶制剂、生物反应器、生物传感器及固定化酶、固定化细胞等生物技术在食品化工中的研究现状和应用以及在食品工业废水处理中的应用进展。 相似文献