全文获取类型
收费全文 | 1897篇 |
免费 | 90篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 36篇 |
综合类 | 4篇 |
化学工业 | 518篇 |
金属工艺 | 68篇 |
机械仪表 | 25篇 |
建筑科学 | 95篇 |
矿业工程 | 10篇 |
能源动力 | 35篇 |
轻工业 | 164篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 137篇 |
一般工业技术 | 433篇 |
冶金工业 | 149篇 |
原子能技术 | 16篇 |
自动化技术 | 297篇 |
出版年
2023年 | 21篇 |
2022年 | 25篇 |
2021年 | 54篇 |
2020年 | 38篇 |
2019年 | 31篇 |
2018年 | 51篇 |
2017年 | 38篇 |
2016年 | 54篇 |
2015年 | 49篇 |
2014年 | 67篇 |
2013年 | 100篇 |
2012年 | 104篇 |
2011年 | 125篇 |
2010年 | 93篇 |
2009年 | 93篇 |
2008年 | 105篇 |
2007年 | 91篇 |
2006年 | 77篇 |
2005年 | 63篇 |
2004年 | 66篇 |
2003年 | 51篇 |
2002年 | 44篇 |
2001年 | 33篇 |
2000年 | 37篇 |
1999年 | 33篇 |
1998年 | 38篇 |
1997年 | 28篇 |
1996年 | 28篇 |
1995年 | 27篇 |
1994年 | 18篇 |
1993年 | 15篇 |
1992年 | 30篇 |
1991年 | 19篇 |
1990年 | 21篇 |
1989年 | 17篇 |
1988年 | 14篇 |
1987年 | 15篇 |
1986年 | 22篇 |
1985年 | 25篇 |
1984年 | 14篇 |
1983年 | 16篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 8篇 |
1977年 | 13篇 |
1976年 | 10篇 |
1975年 | 6篇 |
1974年 | 8篇 |
排序方式: 共有1992条查询结果,搜索用时 15 毫秒
61.
Electronic Markets - 相似文献
62.
Digital Twins are new solution elements to enable ongoing digital monitoring and active functional improvement of interconnected products, devices and machines. In addition, benefits of horizontal and vertical integration in manufacturing are targeted by the introduction of Digital Twins. Using the test environment of smart factory cells, this paper investigates methodological, technological, operative, and business aspects of developing and operating Digital Twins. The following Digital Twin dimensions are considered in scientific and application oriented analysis: (1) integration breadth, (2) connectivity modes, (3) update frequency, (4) CPS intelligence, (5) simulation capabilities, (6) digital model richness, (7) human interaction, and (8) product lifecycle. From this, design elements for the development of Digital Twins are derived and presented. 相似文献
63.
Software and Systems Modeling - 相似文献
64.
Rainer Alt 《Electronic Markets》2018,28(2):123-128
65.
66.
67.
A Novel Technology for Natural Gas Conversion by Means of Integrated Oxidative Coupling and Dry Reforming of Methane
下载免费PDF全文
![点击此处可从《化学,工程师,技术》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Joris W. Thybaut Prof. Guy B. Marin Dr. Claude Mirodatos Dr. Yves Schuurman Dr. Andre C. van Veen Prof. Vladislav A. Sadykov Dr. Helmut Pennemann Dr. Rainer Bellinghausen Prof. Leslaw Mleczko 《化学,工程师,技术》2014,86(11):1855-1870
A novel process concept for the oxidative coupling of methane followed by the oligomerization to liquids has been developed within the frame of the EU integrated project OCMOL. This technology is based on process intensification principles via cutting‐edge structured microreactor technology. It is also a fully integrated industrial process through the re‐use and the recycling of by‐products, in particular CO2, at every process stage. The focus of this contribution is on the reaction engineering aspects of the core steps, i.e., catalysts, kinetics and reactor design for the methane coupling and reforming. 相似文献
68.
Jiraporn Ousingsawat Raquel Centeio Rainer Schreiber Karl Kunzelmann 《International journal of molecular sciences》2022,23(6)
SLC26A9 is an epithelial anion transporter with a poorly defined function in airways. It is assumed to contribute to airway chloride secretion and airway surface hydration. However, immunohistochemistry showing precise localization of SLC26A9 in airways is missing. Some studies report localization near tight junctions, which is difficult to reconcile with a chloride secretory function of SLC26A9. We therefore performed immunocytochemistry of SLC26A9 in sections of human and porcine lungs. Obvious apical localization of SLC26A9 was detected in human and porcine superficial airway epithelia, whereas submucosal glands did not express SLC26A9. The anion transporter was located exclusively in ciliated epithelial cells. Highly differentiated BCi-NS1 human airway epithelial cells grown on permeable supports also expressed SLC26A9 in the apical membrane of ciliated epithelial cells. BCi-NS1 cells expressed the major Cl− transporting proteins CFTR, TMEM16A and SLC26A9 in about equal proportions and produced short-circuit currents activated by increases in intracellular cAMP or Ca2+. Both CFTR and SLC26A9 contribute to basal chloride currents in non-stimulated BCi-NS1 airway epithelia, with CFTR being the dominating Cl− conductance. In wtCFTR-expressing CFBE human airway epithelial cells, SLC26A9 was partially located in the plasma membrane, whereas CFBE cells expressing F508del-CFTR showed exclusive cytosolic localization of SLC26A9. Membrane localization of SLC26A9 and basal chloride currents were augmented by interleukin 13 in wild-type CFTR-expressing cells, but not in cells expressing the most common disease-causing mutant F508del-CFTR. The data suggest an upregulation of SLC26A9-dependent chloride secretion in asthma, but not in the presence of F508del-CFTR. 相似文献
69.
Jrg Brandenburg Rainer Beckert Peer Fehling Manfred Dring Helmar Grls 《Advanced Synthesis \u0026amp; Catalysis》1996,338(1):430-435
Bicyclic Oxalic Amidines as Building Blocks for Highly Substituted 2,2′-Bipyridines and Benzene Derivatives The bis-imidoylchlorides 1 derived from oxalic acid exhibit a high regio- and chemoselectivity. As in the case of 2-picolylamine 2 the acylation with oxalyl chloride furnished the expected open chained oxalic diamides 3a while the imidoylchlorides 1 yield exclusively the new pyrido[1,2-a]-pyrazines 4 . These heterocycles represent readily crystallisable and orange-red coloured compounds with a mesomeric dipolar aromatic substructure. The synthetic value of 4 is based on their easy transformation into highly substituted arenes and hetarenes. Thus, electron deficient dienophiles as dimethyl acetylenedicarboxylate lead to the bipyridines 6 via Hetero-Diels-Alder-Reaction and subsequent 1,5-hydrogen shift. In a complex reaction the derivatives of maleic acid 7a – c yield the bipyridines of type 9 while the new hexasubstituted arenes 10 can be isolated under anaerobic conditions and with an excess of dienophilic component. A x-ray structural determination of 10b shows an alternation of bond lenghts in the benzene ring. This can be considered as a distinct disturbance of aromaticity caused by the arrangement of substituents. 相似文献
70.