首页 | 官方网站   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   167427篇
  免费   11964篇
  国内免费   6000篇
工业技术   185391篇
  2023年   2166篇
  2022年   4006篇
  2021年   6031篇
  2020年   4567篇
  2019年   3922篇
  2018年   5060篇
  2017年   5463篇
  2016年   5053篇
  2015年   5578篇
  2014年   7282篇
  2013年   8941篇
  2012年   9597篇
  2011年   10334篇
  2010年   8757篇
  2009年   8636篇
  2008年   8497篇
  2007年   7983篇
  2006年   7395篇
  2005年   6331篇
  2004年   4851篇
  2003年   4791篇
  2002年   4812篇
  2001年   4399篇
  2000年   3803篇
  1999年   3408篇
  1998年   2947篇
  1997年   2413篇
  1996年   2087篇
  1995年   1805篇
  1994年   1532篇
  1993年   1301篇
  1992年   1233篇
  1991年   1116篇
  1990年   1126篇
  1989年   1038篇
  1988年   932篇
  1987年   863篇
  1986年   789篇
  1985年   750篇
  1984年   720篇
  1982年   687篇
  1981年   688篇
  1979年   748篇
  1978年   794篇
  1977年   758篇
  1976年   794篇
  1975年   723篇
  1974年   731篇
  1973年   729篇
  1972年   709篇
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
101.
Metallurgical and Materials Transactions B - This paper reports a Galerkin finite-element analysis of carbon partitioning from martensite into austenite during the quenching and partitioning...  相似文献   
102.
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   
103.
The influence of the thermal cycling conditions on the thermal-cycling creep of a TN-1 alloy and the related irreversible deformations is studied. The conditions under which an anomalous increase in the irreversible deformations begins are determined. The structural mechanism of the irreversible deformations of an equiatomic alloy is shown to be analogous to the structural mechanism of metal creep at high temperatures: it predominantly has a dislocation character. It is proposed to use the effect of anomalous increase in the deformation of materials with reversible martensitic transformations for forming parts made of these materials at low temperatures.  相似文献   
104.
105.
In order to perform multi-dimensional data aggregation operations efficiently in edge computing-based Internet of things (IoT) systems, a new efficient privacy-preserving multi-dimensional data aggregation (EPMDA) scheme is proposed in this paper. EPMDA scheme is characterized by employing the homomorphic Paillier encryption and SM9 signature algorithm. To improve the computation efficiency of the Paillier encryption operation, EPMDA scheme generates a pre-computed modular exponentiation table of each dimensional data,and the Paillier encryption operation can be implemented by using only several modular multiplications. For the multi-dimensional data, the scheme concatenates zeros between two adjacent dimensional data to avoid data overflow in the sum operation of ciphertexts. To enhance security, EPMDA scheme sets random number at the high address of the exponent. Moreover, the scheme utilizes SM9 signature scheme to guarantee device authentication and data integrity. The performance evaluation and comparison show that EPMDA scheme is more efficient than the existing multi-dimensional data aggregation schemes.  相似文献   
106.
本文提出了一种基于分散加载技术实现Boot程序和用户应用程序在同一个工程编写开发的固件更新方法 .通过编写分散加载规范文件在工程中实现代码存储区分区.为了保证固件更新的稳定性和可靠性,在固件下载过程中引入CRC校验、丢包错包重传等容错技术.实验结果 验证了方法的有效性和可靠性.  相似文献   
107.
Circular data are those for which the natural support is the unit circle and its toroidal extensions. Numerous constructions have been proposed which can be used to generate models for such data. We propose a new, very general, one based on the normalization of the spectra of complex-valued stationary processes. As illustrations of the new construction's application, we study models for univariate circular data obtained from the spectra of autoregressive moving average models and relate them to existing models in the literature. We also propose and investigate multivariate circular models obtained from the high-order spectra of stationary stochastic processes generated using linear filtering with an autoregressive moving average response function. A new family of distributions for a Markov process on the circle is also introduced. Results for asymptotically optimal inference for dependent observations on the circle are presented which provide a new paradigm for inference with circular models. The application of one of the new families of spectra-generated models is illustrated in an analysis of wind direction data.  相似文献   
108.
Russian Engineering Research - The cutting of high-temperature alloys is considered. The performance of solid ceramic end mills is assessed by experimental comparison of five different designs with...  相似文献   
109.
110.
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-23

京公网安备 11010802026262号