全文获取类型
收费全文 | 10487篇 |
免费 | 754篇 |
国内免费 | 311篇 |
专业分类
电工技术 | 396篇 |
综合类 | 391篇 |
化学工业 | 2073篇 |
金属工艺 | 350篇 |
机械仪表 | 574篇 |
建筑科学 | 642篇 |
矿业工程 | 173篇 |
能源动力 | 346篇 |
轻工业 | 641篇 |
水利工程 | 150篇 |
石油天然气 | 273篇 |
武器工业 | 39篇 |
无线电 | 1690篇 |
一般工业技术 | 1511篇 |
冶金工业 | 733篇 |
原子能技术 | 129篇 |
自动化技术 | 1441篇 |
出版年
2024年 | 29篇 |
2023年 | 127篇 |
2022年 | 292篇 |
2021年 | 342篇 |
2020年 | 260篇 |
2019年 | 221篇 |
2018年 | 266篇 |
2017年 | 310篇 |
2016年 | 295篇 |
2015年 | 372篇 |
2014年 | 540篇 |
2013年 | 746篇 |
2012年 | 650篇 |
2011年 | 693篇 |
2010年 | 595篇 |
2009年 | 623篇 |
2008年 | 562篇 |
2007年 | 540篇 |
2006年 | 536篇 |
2005年 | 391篇 |
2004年 | 309篇 |
2003年 | 276篇 |
2002年 | 276篇 |
2001年 | 201篇 |
2000年 | 217篇 |
1999年 | 228篇 |
1998年 | 307篇 |
1997年 | 208篇 |
1996年 | 190篇 |
1995年 | 113篇 |
1994年 | 132篇 |
1993年 | 99篇 |
1992年 | 83篇 |
1991年 | 67篇 |
1990年 | 62篇 |
1989年 | 64篇 |
1988年 | 37篇 |
1987年 | 29篇 |
1986年 | 28篇 |
1985年 | 37篇 |
1984年 | 30篇 |
1983年 | 14篇 |
1982年 | 16篇 |
1981年 | 15篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 14篇 |
1977年 | 16篇 |
1976年 | 20篇 |
1975年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Scientometrics - The article published on 5 July 2021 is well-written and of interest. However, some improvements could be made, such as ten Tables/Figures can be shortened to highlight the focused... 相似文献
2.
Liangtao Yang Liang-Yin Kuo Juan Miguel López del Amo Prasant Kumar Nayak Katherine A. Mazzio Sebastian Maletti Daria Mikhailova Lars Giebeler Payam Kaghazchi Teófilo Rojo Philipp Adelhelm 《Advanced functional materials》2021,31(38):2102939
A known strategy for improving the properties of layered oxide electrodes in sodium-ion batteries is the partial substitution of transition metals by Li. Herein, the role of Li as a defect and its impact on sodium storage in P2-Na0.67Mn0.6Ni0.2Li0.2O2 is discussed. In tandem with electrochemical studies, the electronic and atomic structure are studied using solid-state NMR, operando XRD, and density functional theory (DFT). For the as-synthesized material, Li is located in comparable amounts within the sodium and the transition metal oxide (TMO) layers. Desodiation leads to a redistribution of Li ions within the crystal lattice. During charging, Li ions from the Na layer first migrate to the TMO layer before reversing their course at low Na contents. There is little change in the lattice parameters during charging/discharging, indicating stabilization of the P2 structure. This leads to a solid-solution type storage mechanism (sloping voltage profile) and hence excellent cycle life with a capacity of 110 mAh g-1 after 100 cycles. In contrast, the Li-free compositions Na0.67Mn0.6Ni0.4O2 and Na0.67Mn0.8Ni0.2O2 show phase transitions and a stair-case voltage profile. The capacity is found to originate from mainly Ni3+/Ni4+ and O2-/O2-δ redox processes by DFT, although a small contribution from Mn4+/Mn5+ to the capacity cannot be excluded. 相似文献
3.
Chil-Chyuan Kuo Hsueh-An Liu Chao-Ming Chang 《The International Journal of Advanced Manufacturing Technology》2020,106(9):3775-3785
Vacuum casting is one of the widely used methods for small-volume production of plastic parts. The main challenge of this method is to choose the optimal w 相似文献
4.
This paper is prepared in honour of Professor E.T. Brown for his outstanding contributions to rock mechanics and geotechnical engineering and also for his personal influence on the first author's research career in geomechanics and geotechnical engineering. As a result, we have picked a topic that reflects two key research areas in which Professor E.T. Brown has made seminal contributions over a long and distinguished career. These two areas are concerned with the application of the critical state concept to modelling geomaterials and the analysis of underground excavation or tunnelling in geomaterials.Partially due to Professor Brown's influence, the first author has also been conducting research in these two areas over many years. In particular, this paper aims to describe briefly the development of a unified critical state model for geomaterials together with an application to cavity contraction problems and tunnelling in soils. 相似文献
5.
6.
Dr. Yahu A. Liu Dr. Qihui Jin Qiang Ding Dr. Xueshi Hao Tingting Mo Shanshan Yan Dr. Yefen Zou Dr. Zhihong Huang Xiaoyue Zhang Wenqi Gao Dr. Tom Y.-H. Wu Chun Li Dr. Badry Bursalaya Dr. Michael Di Donato Dr. You-Qing Zhang Lisa Deaton Dr. Weijun Shen Dr. Brandon Taylor Anwesh Kamireddy Dr. George Harb Dr. Jing Li Dr. Yong Jia Dr. Andrew M. Schumacher Dr. Bryan Laffitte Dr. Richard Glynne Dr. Shifeng Pan Dr. Peter McNamara Dr. Valentina Molteni Dr. Jon Loren 《ChemMedChem》2020,15(16):1562-1570
Loss of β-cell mass and function can lead to insufficient insulin levels and ultimately to hyperglycemia and diabetes mellitus. The mainstream treatment approach involves regulation of insulin levels; however, approaches intended to increase β-cell mass are less developed. Promoting β-cell proliferation with low-molecular-weight inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) offers the potential to treat diabetes with oral therapies by restoring β-cell mass, insulin content and glycemic control. GNF4877, a potent dual inhibitor of DYRK1A and glycogen synthase kinase 3β (GSK3β) was previously reported to induce primary human β-cell proliferation in vitro and in vivo. Herein, we describe the lead optimization that lead to the identification of GNF4877 from an aminopyrazine hit identified in a phenotypic high-throughput screening campaign measuring β-cell proliferation. 相似文献
7.
Multifunctional 3D Patternable Drug‐Embedded Nanocarrier‐Based Interfaces to Enhance Signal Recording and Reduce Neuron Degeneration in Neural Implantation 下载免费PDF全文
8.
9.
10.
UML在网络安全监控系统建模中的应用 总被引:4,自引:0,他引:4
本文首先介绍了UML的特性,然后运用UML对网络安全监控系统中的数据采集系统进行了可视化的建模,建立了系统的需求模型和设计模型的各种视图,最后总结了用UML进行系统需求分析和设计的优越性. 相似文献