首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2132篇
  免费   131篇
  国内免费   26篇
电工技术   32篇
综合类   14篇
化学工业   465篇
金属工艺   41篇
机械仪表   81篇
建筑科学   83篇
矿业工程   4篇
能源动力   127篇
轻工业   196篇
水利工程   50篇
石油天然气   34篇
武器工业   2篇
无线电   220篇
一般工业技术   491篇
冶金工业   112篇
原子能技术   13篇
自动化技术   324篇
  2024年   5篇
  2023年   51篇
  2022年   91篇
  2021年   144篇
  2020年   101篇
  2019年   124篇
  2018年   142篇
  2017年   112篇
  2016年   131篇
  2015年   77篇
  2014年   106篇
  2013年   194篇
  2012年   117篇
  2011年   165篇
  2010年   107篇
  2009年   97篇
  2008年   100篇
  2007年   62篇
  2006年   53篇
  2005年   30篇
  2004年   27篇
  2003年   22篇
  2002年   16篇
  2001年   18篇
  2000年   12篇
  1999年   9篇
  1998年   21篇
  1997年   15篇
  1996年   15篇
  1995年   17篇
  1994年   9篇
  1993年   4篇
  1992年   7篇
  1991年   3篇
  1990年   6篇
  1989年   9篇
  1988年   5篇
  1987年   9篇
  1986年   12篇
  1985年   8篇
  1984年   8篇
  1983年   2篇
  1982年   3篇
  1981年   3篇
  1980年   4篇
  1979年   2篇
  1978年   3篇
  1974年   2篇
  1973年   2篇
  1972年   2篇
排序方式: 共有2289条查询结果,搜索用时 31 毫秒
71.
Microsystem Technologies - An alternative actuator for MEMS/NEMS device is proposed and analyzed. The actuator is based on the paired-wires (PW) carrying current concept, which makes the actuator...  相似文献   
72.
Due to the great advances in biomedical digital signal processing, new biometric traits have showed noticeable improvements in authentication systems. Recently, the ElectroCardioGram (ECG) and the PhonoCardioGraph (PCG) have been proposed as novel biometrics. This paper aims to review the previous studies related to the usage of the ECG and PCG signals in human recognition. In addition, we discuss briefly the most important techniques and methodologies used by researchers in the preprocessing, feature extraction and classification of the ECG and PCG signals. At the end, we introduce some future considerations that can be applied in this topic such as: the fusion between different techniques previously used, use both ECG and PCG signals in a multimodal biometric authentication system and building a prototype system for real-time authentication.  相似文献   
73.
Copper and zinc ions were removed from synthetic acidic aqueous solutions onto cement kiln dust (CKD) particles in a single component system. The objectives of this study were to: distinguish between adsorption and precipitation when both mechanisms are occurring simultaneously; define their individual contributions; and consequently, specify the dominant mechanism. This was achieved by conducting a new experimental procedure for the precipitation phase that depended on CKD leachate in combination with a derivation of a simultaneous adsorption-precipitation equation. High removal efficiencies, approaching 100?%, of the Cu and Zn ions, were attained. Precipitation was the dominant mechanism for removing low concentrations of these metals, while adsorption appears to be more significant in removal of high metal concentrations.  相似文献   
74.
This paper presents a comprehensive integrative framework for measuring the performance of customer relationship management (CRM) system based on a detailed empirical study of 32 Iranian internet service provider (ISP) firms. At first, by an extensive literature review and experts who have real practical experiences in the field of CRM, appropriate key performance indicators (KPIs) based on four perspectives of balanced scorecard have been extracted. Then, due to the interdependency and feedback among these KPIs, multiple criteria decision making techniques are used to evaluate CRM performance. Specifically, this study first applies the decision making trial and evaluation laboratory approach to determine the interrelated relationships among criteria, and to find the crucial central and influential factors. Then, the analytical network process method is used to obtain the criterion weights. Finally, according to these previous results, the technique for order of preference by similarity to ideal solution method is adopted to analyze the CRM performance of 32 Iranian ISP firms. The results of this study illustrated that learning and growth is the most crucial influential perspective and it would influence on the other perspectives much more. Furthermore, indicators including organization capital, human capital, customer retention process, customer perceived value, and customer expansion process play an essential role in succeeding of CRM. The results of this study can provide a comprehensive insight for managers into discerning how and through which mechanisms CRM can create merits for the organizations.  相似文献   
75.
76.
77.
Multimedia Tools and Applications - Steganography is the art and science of producing covert communications by concealing secret messages in apparently innocent media, while steganalysis is the art...  相似文献   
78.
79.
80.
The thermoelastic interaction in an unbounded medium with a spherical cavity is studied using two-temperature generalized thermoelasticity theory. The medium is assumed to be initially quiescent. The inner surface of the cavity is taken traction free and subjected to a thermal shock. By the Laplace transformation, the basic equations are expressed in the form of a vector-matrix differential equation, which is solved by an eigenvalue approach. Some comparison have been shown in figures to estimate the effect of the two-temperature parameter.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号