全文获取类型
收费全文 | 763071篇 |
免费 | 64545篇 |
国内免费 | 39532篇 |
专业分类
电工技术 | 68150篇 |
技术理论 | 101篇 |
综合类 | 86819篇 |
化学工业 | 78547篇 |
金属工艺 | 28998篇 |
机械仪表 | 46708篇 |
建筑科学 | 91702篇 |
矿业工程 | 38695篇 |
能源动力 | 26288篇 |
轻工业 | 43398篇 |
水利工程 | 31993篇 |
石油天然气 | 31190篇 |
武器工业 | 9167篇 |
无线电 | 59718篇 |
一般工业技术 | 54489篇 |
冶金工业 | 36358篇 |
原子能技术 | 7060篇 |
自动化技术 | 127767篇 |
出版年
2024年 | 2899篇 |
2023年 | 8618篇 |
2022年 | 16023篇 |
2021年 | 19898篇 |
2020年 | 20738篇 |
2019年 | 16350篇 |
2018年 | 15379篇 |
2017年 | 19416篇 |
2016年 | 23242篇 |
2015年 | 25563篇 |
2014年 | 46360篇 |
2013年 | 42112篇 |
2012年 | 53155篇 |
2011年 | 57136篇 |
2010年 | 43448篇 |
2009年 | 44772篇 |
2008年 | 42808篇 |
2007年 | 53634篇 |
2006年 | 49266篇 |
2005年 | 43301篇 |
2004年 | 37024篇 |
2003年 | 32872篇 |
2002年 | 27148篇 |
2001年 | 22621篇 |
2000年 | 19073篇 |
1999年 | 15457篇 |
1998年 | 11459篇 |
1997年 | 9815篇 |
1996年 | 9465篇 |
1995年 | 7560篇 |
1994年 | 6351篇 |
1993年 | 4387篇 |
1992年 | 3796篇 |
1991年 | 2805篇 |
1990年 | 2399篇 |
1989年 | 1979篇 |
1988年 | 1484篇 |
1987年 | 987篇 |
1986年 | 792篇 |
1985年 | 818篇 |
1984年 | 840篇 |
1983年 | 744篇 |
1982年 | 595篇 |
1981年 | 580篇 |
1980年 | 364篇 |
1979年 | 243篇 |
1978年 | 167篇 |
1977年 | 145篇 |
1976年 | 99篇 |
1975年 | 100篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Jean-Claude Malela-Majika Sandile Charles Shongwe Olatunde Adebayo Adeoti 《Quality and Reliability Engineering International》2021,37(8):3314-3322
The sensitivity of a monitoring scheme depends on many factors including the variance of the charting statistic which is very important in the computation of the control limits. This paper discusses the computation of the variance of the recently proposed hybrid homogeneously weighted moving average (HHWMA) scheme which was based on an incorrect assumption. The correct variance is used to evaluate the run-length characteristics of the HHWMA scheme. It is observed that the incorrect variance has a significant impact on the sensitivity (or performance) of the HHWMA scheme. 相似文献
3.
Elli Ntakou Ralph Masiello Farnaz Farzan Shay Bahramirad Aleksi Paaso M.A. Nayeem Maigha Maigha Daniel Kushner 《The Electricity Journal》2019,32(4):45-49
This paper presents part of the work ComEd and Quanta Technology have performed to quantify the locational and temporal value of DER to avoid distribution grid upgrade investments. It focuses on the formulation of a robust and efficient algorithm for DER optimal dispatch on a distribution feeder to mitigate the violation of current and voltage limits using the allocated cost of capacity and locational marginal value of real and reactive DER injection/withdrawal. 相似文献
4.
Structural health monitoring system based on multi-agent coordination and fusion for large structure
In practical applications of structural health monitoring technology, a large number of distributed sensors are usually adopted to monitor the big dimension structures and different kinds of damage. The monitored structures are usually divided into different sub-structures and monitored by different sensor sets. Under this situation, how to manage the distributed sensor set and fuse different methods to obtain a fast and accurate evaluation result is an important problem to be addressed deeply. In the paper, a multi-agent fusion and coordination system is presented to deal with the damage identification for the strain distribution and joint failure in the large structure. Firstly, the monitoring system is adopted to distributedly monitor two kinds of damages, and it self-judges whether the static load happens in the monitored sub-region, and focuses on the static load on the sub-region boundary to obtain the sensor network information with blackboard model. Then, the improved contract net protocol is used to dynamically distribute the damage evaluation module for monitoring two kinds of damage uninterruptedly. Lastly, a reliable assessment for the whole structure is given by combing various heterogeneous classifiers strengths with voting-based fusion. The proposed multi-agent system is illustrated through a large aerospace aluminum plate structure experiment. The result shows that the method can significantly improve the monitoring performance for the large-scale structure. 相似文献
5.
One specific class of non-linear evolution equations, known as the Tzitzéica-type equations, has received great attention from a group of researchers involved in non-linear science. In this article, new exact solutions of the Tzitzéica-type equations arising in non-linear optics, including the Tzitzéica, Dodd–Bullough–Mikhailov and Tzitzéica–Dodd–Bullough equations, are obtained using the expa function method. The integration technique actually suggests a useful and reliable method to extract new exact solutions of a wide range of non-linear evolution equations. 相似文献
6.
7.
一场新型冠状病毒肺炎疫情的爆发给染料行业的发展带来了影响,既有负面消极,也有积极影响。疫情将促进染料行业绿色发展,推动染料行业走向信息化、智能化时代,走向高质量发展,指出只要坚持绿色、创新和智能化,就能战胜疫情,推动中国染料行业稳健发展。 相似文献
8.
Yasoub Eghbali Mahmoud Ferdosizade Naeiny 《International Journal of Communication Systems》2020,33(14)
In this paper, an off‐grid direction of arrival (DoA) estimation method is proposed for wideband signals. This method is based on the sparse representation (SR) of the array covariance matrix. Similar to the time domain DoA estimation methods, the correlation function of the sources was assumed to be the same and known. A new measurement vector is obtained using the lower‐left triangular elements of the covariance matrix. The DoAs are estimated by quantizing the entire range of continuous angle space into discrete grid points. However, the exact DoAs may be located between two grid points; therefore, this estimation has errors. The accuracy of DoA estimation is improved by the minimization of the difference between the new measurement vector and its estimated values. Simulation results revealed that the proposed method can enhance the DoA estimation accuracy of wideband signals. 相似文献
9.
10.
在干扰条件下,卫星导航抗干扰波束形成算法往往需要卫星信号波达方向(Direction-of-Arrival,DOA)的先验信息。但当存在低信噪比信号或主动干扰源时,常规的DOA估计算法性能急剧下降甚至失效。针对此问题,提出了一种被干扰信号压制的低信噪比“北斗”信号的DOA估计算法。该算法首先通过对接收信号进行子空间投影抑制干扰信号,然后对抑制干扰后的信号进行解扩重构处理,最后通过多重信号分类算法完成对“北斗”信号的DOA估计。仿真结果表明,在干扰信号干信比80 dB条件下,“北斗”信号DOA估计误差在5°以内,为下一步进行波束形成计算提供了高精度的入射角信息。 相似文献