全文获取类型
收费全文 | 16392篇 |
免费 | 1295篇 |
国内免费 | 727篇 |
专业分类
电工技术 | 1498篇 |
综合类 | 1020篇 |
化学工业 | 4120篇 |
金属工艺 | 1639篇 |
机械仪表 | 847篇 |
建筑科学 | 877篇 |
矿业工程 | 484篇 |
能源动力 | 1384篇 |
轻工业 | 1716篇 |
水利工程 | 344篇 |
石油天然气 | 403篇 |
武器工业 | 53篇 |
无线电 | 882篇 |
一般工业技术 | 1482篇 |
冶金工业 | 994篇 |
原子能技术 | 143篇 |
自动化技术 | 528篇 |
出版年
2024年 | 61篇 |
2023年 | 228篇 |
2022年 | 373篇 |
2021年 | 495篇 |
2020年 | 526篇 |
2019年 | 464篇 |
2018年 | 393篇 |
2017年 | 526篇 |
2016年 | 532篇 |
2015年 | 511篇 |
2014年 | 867篇 |
2013年 | 903篇 |
2012年 | 1018篇 |
2011年 | 1314篇 |
2010年 | 982篇 |
2009年 | 998篇 |
2008年 | 862篇 |
2007年 | 1165篇 |
2006年 | 1035篇 |
2005年 | 836篇 |
2004年 | 704篇 |
2003年 | 609篇 |
2002年 | 543篇 |
2001年 | 459篇 |
2000年 | 381篇 |
1999年 | 305篇 |
1998年 | 255篇 |
1997年 | 198篇 |
1996年 | 154篇 |
1995年 | 149篇 |
1994年 | 145篇 |
1993年 | 96篇 |
1992年 | 73篇 |
1991年 | 55篇 |
1990年 | 42篇 |
1989年 | 36篇 |
1988年 | 34篇 |
1987年 | 12篇 |
1986年 | 16篇 |
1985年 | 21篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1964年 | 1篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
92.
Jian‐Peng Cui Feng Zhou Chengqun Song Quan‐Min Zhong Qiong‐Hua Wang 《Journal of the Society for Information Display》2012,20(6):347-350
Abstract— A low‐voltage (~10 Vrms) and high‐transmittance (~90%) polymer‐stabilized blue‐phase liquid‐crystal (BPLC) device with a slanted‐electrodes structure is proposed. Unlike the vertical‐field‐switching (VFS) mode in which oblique incident light and a vertical field are employed, the proposed device utilizes normal incident light and an oblique field. The slanted electrodes generate a strong and uniform oblique electric field, which contributes in obtaining low voltage and high transmittance. Moreover, no couple films or prism sheets are needed, which helps to enhance the optical efficiency and simplify of the device structure. This device has great potential application for emerging BPLC displays and photonic devices. 相似文献
93.
94.
制备了基于一种简单的金属铜配合物2,4-二羟基苯甲酸铜(Ⅱ)(Cu(Ⅱ)DHBA)为载体的PVC膜硫氰酸根离子(SCN-)选择性电极。该电极在1.0×10-1~1.0×10-6mol/LSCN-浓度范围内呈现斜率为-59.5mV/dec的近Nernst电位响应,检测下限为9.1×10-7mol/L。利用紫外可见光谱及交流阻抗技术初步探讨了电极对SCN-呈现的选择性电位响应机理。该电极作为直接电位分析法的指示电极,成功运用于实验室废水中硫氰酸盐含量的测定。 相似文献
95.
Electrochemical investigation of the iron-containing and no iron-containing AB5-type negative electrodes 总被引:2,自引:0,他引:2
M. Tliha C. Khaldi H. Mathlouthi J. Lamloumi A. Percheron-Gugan 《Journal of Alloys and Compounds》2007,440(1-2):323-327
The electrochemical behaviour of LaNi3.55Mn0.4Al0.3Co0.75−xFex (x = 0, 0.15, 0.55, 0.75) intermetallic compounds has been studied and presented [C. Khaldi, H. Mathlouthi, J. Lamloumi, A. Percheron-Guégan, Int. J. Hydrogen Energy 29 (2004) 307–311; C. Khaldi, H. Mathlouthi, J. Lamloumi, A. Percheron-Guégan, J. Alloys Compd. 360 (2003) 266–271; C. Khaldi, H. Mathlouthi, J. Lamloumi, A. Percheron-Guégan, J. Alloys Compd. 384 (2004) 249–253]. It has been deduced that the LaNi3.55Mn0.4Al0.3Co0.4Fe0.35 compound has interesting electrochemical properties. In this paper we present the electrochemical study of LaNi3.55Mn0.4Al0.3Co0.4Fe0.35 compound properties compared with the parent LaNi3.55Mn0.4Al0.3Co0.75 compound. Several techniques, such as, the chronopotentiometry, the constant potential discharge (CPD), the cyclic voltammetry (CV) and the linear polarization (LP) were applied to characterize these electrochemical properties. The electrochemical discharge capacity of the LaNi3.55Mn0.4Al0.3Co0.75 alloy increases to reach 294 mAh g−1 after few cycles only (five cycles). However, the activation of the LaNi3.55Mn0.4Al0.3Co0.4Fe0.35 alloy takes more than 20 cycles to be achieved and the obtained maximum discharge capacity is 194 mAh g−1. The hydrogen diffusion coefficient DH was determined by constant potential discharge and cyclic voltammetry techniques. The obtained values of the LaNi3.55Mn0.4Al0.3Co0.75 and LaNi3.55Mn0.4Al0.3Co0.4Fe0.35 compounds are 6.29 × 10−11 and 7.62 × 10−11, and 2 × 10−8 and 7.5 × 10−8 cm2 s−1 by CPD and CV techniques, respectively. The exchange current density values, determined by a linear polarization technique, are 44 and 27 mA g−1, respectively, for LaNi3.55Mn0.4Al0.3Co0.75 and LaNi3.55Mn0.4Al0.3Co0.4Fe0.35 alloys. 相似文献
96.
97.
二元稀土系AB5型贮氢电极合金的放电容量与晶胞体积和4f电子浓度的关系 总被引:3,自引:0,他引:3
制备了6个系列通式为AαA‘1-αB5的RE(NiCoMnTi)5贮氢电极合金(其中,AαA‘1-α为La,Ce,Pr,Nd4个元素中任意2个的组合),测定了它们在100次循环中的最大放电容量Cmax及部分合金的晶胞体积Vcell.结果表明:Cmax主要由Vcell决定,Cmax先随Vcell的增大而增加,在Vcell≈85.66x10^-^3。nm^3时达到一极大值,然后又随Vcell的增大而减小;同时,Cmax还与4f电子浓度ne4f/naRE有关,A侧具有相同4f电子浓度的合金其Cmax随4f电子浓度的变化趋势相似. 相似文献
98.
Weihang Sun Dongfang Liu Minghui Zhang 《Frontiers of Chemical Science and Engineering》2021,15(6):1427
The dye industry produces a large amount of hazardous wastewater every day worldwide, which brings potential threaten to the global environment. As an excellent method for removal of water chroma and chemical oxygen demand, electrocatalytic methods are currently widely used in the treatment of dye wastewater. The selection and preparation of electrode materials and electrocatalysts play an important role on the electrocatalytic treatment. The aim of this paper is to introduce the most excellent high-efficiency electrode materials and electrocatalysts in the field of dye wastewater treatment. Many electrode materials such as metal electrode materials, boron-doped diamond anode materials and three-dimensional electrode are introduced in detail. Besides, the mechanism of electrocatalytic oxidation is summarized. The composite treatment of active electrode and electrocatalyst are extensively examined. Finally, the progress of photo-assisted electrocatalytic methods of dye wastewater and the catalysts are described. 相似文献
99.
利用二硫化钼和葡萄糖为原料,采用一锅乙醇/水复合溶剂热-后热处理法制备了绣球花状结构MoS2/C复合材料。考查了乙醇/水复合溶剂的合理组成和MoS2/C复合材料中碳的合理含量,分别采用SEM和TEM表征了MoS2/C材料的形貌结构,通过TGA测试和计算了材料中的碳含量。采用循环伏安、恒流充放电和交流阻抗等测试了MoS2/C复合电极的电化学性能。结果表明,MoS2/C复合材料拥有多级花球状结构,缓解了MoS2的团聚,使电极材料的利用率和电化学稳定性显著提高。当V(乙醇):V(水)为1:2,碳含量为50%时,MoS2/C复合电极在200 mA·g-1的电流密度下,充放电循环100次后,可逆容量达到762 mA·h·g-1。 相似文献
100.
Muhammad Khurram Tufail Niaz Ahmad Le Yang Lei Zhou Muhammad Adnan Naseer Renjie Chen Wen Yang 《中国化学工程学报》2021,39(11):16-36
The development of an inorganic electrochemical stable solid-state electrolyte is essentially responsible for future state-of-the-art all-solid-state lithium batteries (ASSLBs). Because of their advantages in safety, working temperature, high energy density, and packaging, ASSLBs can develop an ideal energy storage system for modern electric vehicles (EVs). A solid electrolyte (SE) model must have an economical synthesis approach, exhibit electrochemical and chemical stability, high ionic conductivity, and low interfacial resistance. Owing to its highest conductivity of 17 mS·cm-1, and deformability, the sulfide-based Li7P3S11 solid electrolyte is a promising contender for the high-performance bulk type of ASSLBs. Herein, we present a current glimpse of the progress of synthetic procedures, structural aspects, and ionic conductivity improvement strategies. Structural elucidation and mechanistic approaches have been extensively discussed by using various characterization techniques. The chemical stability of Li7P3S11 could be enhanced via oxide doping, and hard and soft acid/base (HSAB) concepts are also discussed. The issues to be undertaken for designing the ideal solid electrolytes, interfacial challenges, and high energy density have been discoursed. This review aims to provide a bird's eye view of the recent development of Li7P3S11-based solid-state electrolyte applications and explore the strategies for designing new solid electrolytes with a target-oriented approach to enhance the efficiency of high energy density all-solid-state lithium batteries. 相似文献