全文获取类型
收费全文 | 7809篇 |
免费 | 601篇 |
国内免费 | 249篇 |
专业分类
电工技术 | 448篇 |
技术理论 | 1篇 |
综合类 | 509篇 |
化学工业 | 1301篇 |
金属工艺 | 331篇 |
机械仪表 | 411篇 |
建筑科学 | 523篇 |
矿业工程 | 210篇 |
能源动力 | 229篇 |
轻工业 | 713篇 |
水利工程 | 139篇 |
石油天然气 | 465篇 |
武器工业 | 58篇 |
无线电 | 697篇 |
一般工业技术 | 943篇 |
冶金工业 | 646篇 |
原子能技术 | 83篇 |
自动化技术 | 952篇 |
出版年
2024年 | 33篇 |
2023年 | 120篇 |
2022年 | 199篇 |
2021年 | 297篇 |
2020年 | 216篇 |
2019年 | 193篇 |
2018年 | 243篇 |
2017年 | 255篇 |
2016年 | 232篇 |
2015年 | 292篇 |
2014年 | 393篇 |
2013年 | 493篇 |
2012年 | 488篇 |
2011年 | 543篇 |
2010年 | 440篇 |
2009年 | 405篇 |
2008年 | 426篇 |
2007年 | 407篇 |
2006年 | 419篇 |
2005年 | 311篇 |
2004年 | 235篇 |
2003年 | 209篇 |
2002年 | 191篇 |
2001年 | 202篇 |
2000年 | 169篇 |
1999年 | 182篇 |
1998年 | 260篇 |
1997年 | 186篇 |
1996年 | 127篇 |
1995年 | 106篇 |
1994年 | 90篇 |
1993年 | 65篇 |
1992年 | 38篇 |
1991年 | 28篇 |
1990年 | 19篇 |
1989年 | 20篇 |
1988年 | 21篇 |
1987年 | 13篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 10篇 |
1976年 | 11篇 |
1974年 | 3篇 |
1959年 | 7篇 |
排序方式: 共有8659条查询结果,搜索用时 15 毫秒
71.
Jae‐Hyung Lee Ji‐Hong Kim Gyu‐Ho Lim Tae‐Hoon Kim Jung‐Hwan Lee Kyung‐Hwan Park Mu‐Hun Park Pan‐Bong Ha Young‐Hee Kim 《ETRI Journal》2008,30(3):347-354
In this paper, the design of a low‐power 512‐bit synchronous EEPROM for a passive UHF RFID tag chip is presented. We apply low‐power schemes, such as dual power supply voltage (VDD=1.5 V and VDDP=2.5 V), clocked inverter sensing, voltage‐up converter, I/O interface, and Dickson charge pump using Schottky diode. An EEPROM is fabricated with the 0.25 μm EEPROM process. Power dissipation is 32.78 μW in the read cycle and 78.05 μW in the write cycle. The layout size is 449.3 μm × 480.67 μm. 相似文献
72.
Jamshid Sangirov Ikechi Augustine Ukaegbu Tae‐Woo Lee Mu Hee Cho Hyo‐Hoon Park 《ETRI Journal》2012,34(1):122-125
A video signal through a high‐density optical link has been demonstrated to show the reliability of optical link for high‐data‐rate transmission. To reduce optical point‐to‐point links, an electrical link has been utilized for control and clock signaling. The latency and flicker with background noise occurred during the transferring of data across the optical link due to electrical‐to‐optical with optical‐to‐electrical conversions. The proposed synchronization technology combined with a flicker and denoising algorithm has given good results and can be applied in high‐definition serial data interface (HD‐SDI), ultra‐HD‐SDI, and HD multimedia interface transmission system applications. 相似文献
73.
This paper presents a detailed analysis of some classes of stable multivariate polynomials. The main aim of the analysis is to give conditions under which polynomials preserve stability when they are subjected to small coefficient variations. The maximal class of such polynomials is introduced. Some basic properties of polynomials from this class are obtained. 相似文献
74.
针对当前分割方法不能兼顾可见光与近红外光谱的异质噪声虹膜图像的分割精度与效率问题,提出一种基于注意力机制与密集多尺度特征融合的编-解码网络.首先,引入基于深度可分离卷积的改进残差瓶颈单元,降低参数量与计算量的同时防止信息丢失与梯度混淆;其次,改进密集空洞空间金字塔模块的空洞率组合并放置于编码器后,以增强多尺度特征融合;... 相似文献
75.
76.
77.
随着互联网技术的迅猛发展,互联网金融应运而生,构成国家经济积极发展的重要组成部分,而互联网金融风险问题亟待解决。文章根据传统金融的风险特点,建立互联网金融风险二级指标,基于模糊层次分析法构建模型,对互联网金融风险进行定量分析评估。实证结果显示互联网金融信用风险和运营风险为主要风险,为未来风险防控和风险监管提供了参考依据。 相似文献
78.
Yurou Zhang Dohyung Kim Jung-Ho Yun Jongchul Lim Min-Cherl Jung Xiaoming Wen Jan Seidel Eunyoung Choi Mu Xiao Tengfei Qiu Miaoqiang Lyu EQ Han Mehri Ghasemi Sean Lim Henry J. Snaith Jae Sung Yun Lianzhou Wang 《Advanced functional materials》2021,31(50):2105542
Organometal perovskite single crystals have been recognized as a promising platform for high-performance optoelectronic devices, featuring high crystallinity and stability. However, a high trap density and structural nonuniformity at the surface have been major barriers to the progress of single crystal-based optoelectronic devices. Here, the formation of a unique nanoisland structure is reported at the surface of the facet-controlled cuboid MAPbI3 (MA = CH3NH3+) single crystals through a cation interdiffusion process enabled by energetically vaporized CsI. The interdiffusion of mobile ions between the bulk and the surface is triggered by thermally activated CsI vapor, which reconstructs the surface that is rich in MA and CsI with reduced dangling bonds. Simultaneously, an array of Cs-Pb-rich nanoislands is constructed on the surface of the MAPbI3 single crystals. This newly reconstructed nanoisland surface enhances the light absorbance over 50% and increases the charge carrier mobility from 56 to 93 cm2 V−1 s−1. As confirmed by Kelvin probe force microscopy, the nanoislands form a gradient band bending that prevents recombination of excess carriers, and thus, enhances lateral carrier transport properties. This unique engineering of the single crystal surface provides a pathway towards developing high-quality perovskite single-crystal surface for optoelectronic applications. 相似文献
79.
Lu-Kang Zhao Xuan-Wen Gao Jianjia Mu Wen-Bin Luo Zhaomeng Liu Zhenhua Sun Qin-Fen Gu Feng Li 《Advanced functional materials》2023,33(41):2304292
K-metal batteries have become one of the promising candidates for the large-scale energy storage owing to the virtually inexhaustible and widely potassium resources. The uneven K+ deposition and dendrite growth on the anode causes the batteries prematurely failure to limit the further application. An integrated K-metal anode is constructed by cold-rolling K metal with a potassiphilic porous interconnected mediator. Based on the experimental results and theoretical calculations, it demonstrates that the potassiphilic porous interconnected mediator boosts the mass transportation of K-metal anode by the K affinity enhancement, which decreases the concentration polarization and makes a dendrite-free K-metal anode interface. The interconnected porous structure mitigates the internal stress generated during repetitive deposition/stripping, enabling minimized the generation of electrode collapse. As a result, a durable K-metal anode with excellent cycling ability of exceed 1, 000 h at 1 mA cm−2/1 mAh cm−2 and lower polarization voltage in carbonate electrolyte is obtained. This proposed integrated anode with fast K+ kinetics fabricated by a repeated cold rolling and folding process provides a new avenue for constructing a high-performance dendrites-free anode for K-metal batteries. 相似文献
80.
A method for measuring the frequency stability of tunable laser is proposed by using confocal Fabry-Perot(F-P)interferometer.The F-P interferometer is used to get the output frequency of the laser as a reference,and the method eliminates the need of an independent optical source as a frequency reference.Using this technique,the frequency stability of the tunable external-cavity diode laser(ECDL)is measured to be 2.26×10~(-9)with an integration time of 20 ms. 相似文献