全文获取类型
收费全文 | 5603篇 |
免费 | 281篇 |
国内免费 | 193篇 |
专业分类
电工技术 | 156篇 |
技术理论 | 1篇 |
综合类 | 175篇 |
化学工业 | 652篇 |
金属工艺 | 182篇 |
机械仪表 | 205篇 |
建筑科学 | 310篇 |
矿业工程 | 107篇 |
能源动力 | 115篇 |
轻工业 | 221篇 |
水利工程 | 56篇 |
石油天然气 | 218篇 |
武器工业 | 17篇 |
无线电 | 471篇 |
一般工业技术 | 450篇 |
冶金工业 | 2043篇 |
原子能技术 | 51篇 |
自动化技术 | 647篇 |
出版年
2024年 | 20篇 |
2023年 | 54篇 |
2022年 | 126篇 |
2021年 | 138篇 |
2020年 | 103篇 |
2019年 | 97篇 |
2018年 | 119篇 |
2017年 | 126篇 |
2016年 | 99篇 |
2015年 | 140篇 |
2014年 | 162篇 |
2013年 | 231篇 |
2012年 | 218篇 |
2011年 | 253篇 |
2010年 | 207篇 |
2009年 | 218篇 |
2008年 | 190篇 |
2007年 | 195篇 |
2006年 | 169篇 |
2005年 | 178篇 |
2004年 | 114篇 |
2003年 | 93篇 |
2002年 | 92篇 |
2001年 | 84篇 |
2000年 | 120篇 |
1999年 | 179篇 |
1998年 | 725篇 |
1997年 | 426篇 |
1996年 | 276篇 |
1995年 | 192篇 |
1994年 | 138篇 |
1993年 | 148篇 |
1992年 | 38篇 |
1991年 | 52篇 |
1990年 | 48篇 |
1989年 | 40篇 |
1988年 | 41篇 |
1987年 | 29篇 |
1986年 | 30篇 |
1985年 | 19篇 |
1984年 | 3篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 15篇 |
1978年 | 4篇 |
1977年 | 22篇 |
1976年 | 72篇 |
1969年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有6077条查询结果,搜索用时 15 毫秒
81.
Gan Zhihua Chai Xiuli Zhi Xiangcheng Ding Wenke Lu Yang Wu Xiangjun 《Neural computing & applications》2021,33(23):16251-16277
Neural Computing and Applications - In this paper, an image cipher is presented based on DNA sequence operations, image filtering and memrisitve chaotic system. Firstly, plain image is preprocessed... 相似文献
82.
Gan Zhihua Bi Jianqiang Ding Wenke Chai Xiuli 《Neural computing & applications》2021,33(19):12845-12867
Neural Computing and Applications - Compared to 1D compressed sensing (CS), 2D CS is more efficient for compressing the plaintext image from two directions, but security level of current 2D... 相似文献
83.
利用LabVIEW设计了惯性测量单元信号采集及处理软件,主要包括串口通信、数据分离及信号处理等模块;串口通信模块采用VISA方式编程,建立了惯性测量单元与上位机之间的通信;根据惯性测量单元输出数据的格式,利用LabVIEW中的匹配模式函数分离出沿三轴向的加速度信号和角速率信号;设计了一种用于去除加速度信号中低频成份的数字滤波器;在建立的陀螺漂移模型基础上,分别进行小波基、小波分解层数、阈值函数及阈值估计方法等小波参数的选取. 相似文献
84.
Feng Zhong Chai Kiat Yeo Bu Sung Lee 《Journal of Network and Computer Applications》2012,35(1):316-327
In places where mobile users can access multiple wireless networks simultaneously, a multipath scheduling algorithm can benefit the performance of wireless networks and improve the experience of mobile users. However, existing literature shows that it may not be the case, especially for TCP flows. According to early investigations, there are mainly two reasons that result in bad performance of TCP flows in wireless networks. One is the occurrence of out-of-order packets due to different delays in multiple paths. The other is the packet loss which is resulted from the limited bandwidth of wireless networks. To better exploit multipath scheduling for TCP flows, this paper presents a new scheduling algorithm named Adaptive Load Balancing Algorithm (ALBAM) to split traffic across multiple wireless links within the ISP infrastructure. Targeting at solving the two adverse impacts on TCP flows, ALBAM develops two techniques. Firstly, ALBAM takes advantage of the bursty nature of TCP flows and performs scheduling at the flowlet granularity where the packet interval is large enough to compensate for the different path delays. Secondly, ALBAM develops a Packet Number Estimation Algorithm (PNEA) to predict the buffer usage in each path. With PNEA, ALBAM can prevent buffer overflow and schedule the TCP flow to a less congested path before it suffers packet loss. Simulations show that ALBAM can provide better performance to TCP connections than its other counterparts. 相似文献
85.
Real-time and reliable measurements of the effluent quality are essential to improve operating efficiency and reduce energy consumption for the wastewater treatment process.Due to the low accuracy and unstable performance of the traditional effluent quality measurements,we propose a selective ensemble extreme learning machine modeling method to enhance the effluent quality predictions.Extreme learning machine algorithm is inserted into a selective ensemble frame as the component model since it runs much faster and provides better generalization performance than other popular learning algorithms.Ensemble extreme learning machine models overcome variations in different trials of simulations for single model.Selective ensemble based on genetic algorithm is used to further exclude some bad components from all the available ensembles in order to reduce the computation complexity and improve the generalization performance.The proposed method is verified with the data from an industrial wastewater treatment plant,located in Shenyang,China.Experimental results show that the proposed method has relatively stronger generalization and higher accuracy than partial least square,neural network partial least square,single extreme learning machine and ensemble extreme learning machine model. 相似文献
86.
87.
This paper studied the changing principles of carbon content in direct reduction iron (DRI) and liquid iron in the COREX melting gasifier. Under the normal working conditions of experimental equipment, liquid nitrogen was poured into the melting gasifier from its tuyere to cool down quickly. And then seven cross sections were made to study the carburization reaction and its characteristics of the solid iron and the liquid iron, and also the reaction of carbon between the slag and the metal. According to the results, the influences of the thickness of the semi-coke layer and the temperature on the carbon content of liquid iron in the COREX melting gasifier were confirmed. 相似文献
88.
Chai Linjiang Xia Jiying Murty Korukonda L. Gu Xinfu Fan Jiangkun Yao Zhongwen 《Metallurgical and Materials Transactions A》2022,53(8):3179-3193
Metallurgical and Materials Transactions A - A hot-rolled Ti–6Al–4V sheet was annealed at 960 °C (sub β-transus temperature) and then subjected to different coolings [in water... 相似文献
89.
镁基复合材料微区力学状态的有限元分析 总被引:3,自引:0,他引:3
弹性变形范围内,在采用三维有限元模型分析了颗粒增强Mg基复合材料(PRMMCs)中,颗粒的分布形态对材料微区力学状态的影响。结果表明,在保持颗粒长径比(2:1)和颗粒间距(d)不变的情况下,随着θ的变化,不存在颗粒断裂的危险,材料的主要失效方式为界面脱离和基体开裂。增强体相对夹角θ=15o时的结果优于其它情况,这更有利于充分发挥材料的性能。 相似文献
90.
粉末冶金法制备SiC晶须增强MB15镁基复合材料 总被引:6,自引:0,他引:6
采用粉末冶金法制备了SiC晶须增强镁基复合材料(SiCW/MB15)试样。通过检测基体显微硬度探讨了SiCW对镁合金时效规律的影响,并借助扫描电镜(SEM)、透射电镜(TEM)和拉伸试验,研究了混粉方式对复合材料室温力学性能、SiCW分布及显微结构的影响。结果表明,MB15及其复合材料的时效硬化曲线上均存在双峰现象;SiCW的加入既提高了MB5的硬度,又加快了其时效速度:混粉方式对晶须分布及SiCW/MB15复合材料的室温力学性能影响很大。 相似文献