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   3032篇
  免费   352篇
  国内免费   251篇
电工技术   216篇
技术理论   1篇
综合类   383篇
化学工业   85篇
金属工艺   43篇
机械仪表   201篇
建筑科学   453篇
矿业工程   56篇
能源动力   264篇
轻工业   35篇
水利工程   95篇
石油天然气   47篇
武器工业   33篇
无线电   500篇
一般工业技术   529篇
冶金工业   74篇
原子能技术   18篇
自动化技术   602篇
  2024年   5篇
  2023年   39篇
  2022年   50篇
  2021年   84篇
  2020年   113篇
  2019年   97篇
  2018年   82篇
  2017年   102篇
  2016年   111篇
  2015年   125篇
  2014年   173篇
  2013年   243篇
  2012年   185篇
  2011年   230篇
  2010年   200篇
  2009年   205篇
  2008年   195篇
  2007年   234篇
  2006年   190篇
  2005年   149篇
  2004年   131篇
  2003年   113篇
  2002年   84篇
  2001年   66篇
  2000年   78篇
  1999年   63篇
  1998年   49篇
  1997年   50篇
  1996年   36篇
  1995年   33篇
  1994年   24篇
  1993年   26篇
  1992年   14篇
  1991年   19篇
  1990年   13篇
  1989年   6篇
  1988年   3篇
  1987年   5篇
  1986年   2篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1980年   2篇
排序方式: 共有3635条查询结果,搜索用时 406 毫秒
1.
This paper explores the process of public sector reform in Greece through the lens of privatisation. It is suggested that the transformation of the domestic post-war interventionist state into the current market-oriented paradigm has been disrupted and dependent on changing reform rationales. Along with the effect of historical dynamics on the direction and scale of change, the explanatory power of external determinants of reform is stressed. Findings reflect a direct linkage between the intensity of external pressure and the pace of reforms. The sustainability of gradual privatisation reforms seems more certain than the outcomes of fast-track privatisations under policy conditionality.  相似文献   
2.
3.
Decarbonization of the energy system is urgent to avert the disruptions in the climate. Considering its share, the low carbon transition of the power sector is pivotal. Growing electricity demand poses unique challenges for Turkey to enact deep decarbonization. It is vital to uncover the contributing causes of emissions to provide strategic oversight for carbon management activities. This study investigates key drivers of CO2 emissions from the power sector using the Logarithmic Mean Divisia Index decomposition method. While efficiency improvement contributes to sustainable yet minor mitigation, changes in the fossil-fuel share indicate a cycling but significant overall impact.  相似文献   
4.
Abstract. This paper describes artificial neural network based pure significance tests for the unit root hypothesis against nonlinear alternatives. The theoretical properties of the tests are discussed and a Monte Carlo investigation of their small sample properties is undertaken.  相似文献   
5.
本文提出了求解非线性问题的一种新方法——逐次迭代法,本方法先是给出一个初始近似解,然后将这个近似解进行校正迭代,使之接近于真实解,把一个非线性问题转化为一个线性问题来解决。  相似文献   
6.
In control systems, actuators often have nonlinear characteristics that can not be neglected. For linear systems driven by actuators satisfying the generalized sector condition, a robust state feedback controller synthesis method is proposed to achieve the ultimate boundedness control. The method is based on the linear matrix inequality approach and is easy to apply. As an important special case of the generalized sector condition, the saturation characteristic of actuators is discussed separately, and non‐conservative results are obtained.  相似文献   
7.
本文给出了二阶非线性微分方程的一个新的振动准则。所得结果改进了若干熟知的振动准则。  相似文献   
8.
When using a conventional demodulator, a sufficient condition to maintain ODS-CDMA codeword orthogonality is constant relative channel amplitude over the codeword duration. When transmitted over a memoryless, AM/PM nonlinearity channel, the chip-to-chip fluctuating amplitude of a composite ODS-CDMA QPSK waveform produces a chip-to-chip fluctuating phase that deorthogonalizes the ODS-CDMA codewords, resulting in an additional multiple access self-interference similar to that found in asynchronous DS-CDMA. For ODS-CDMA QPSK in an AM/PM nonlinearity channel, we utilize the Central Limit Theorem, derive, and evaluate: (i) an expression for the signal-to-distortion ratio at the demodulator output, (ii) an expression for the uncoded bit error probability, and (iii) an upper bound on the convolutionally-coded bit error probability. We find that the degradation to BER depends on both the AM/PM nonlinearity slope and the ODS-CDMA channel loading.  相似文献   
9.
随着国有企业改革的不断深化,市场竞争愈加激烈,针对机械行业的现状,从3个方面探讨了强化管理机制,推进机械制造企业可持续快速发展的途径.  相似文献   
10.
From the results reported here it is suggested that policy decisions about the potential contribution of decentralized energy supply systems to UK industrial energy requirements should be based on the suitability of individual sectors rather than averaged over all sectors. The suitability of decentralized energy sources is evaluated, based on a themodynamic match between source and demand. This suitability criterion is used to identify the most appropriate sector in manufacturing industries for the adoption of decentralized energy supply, leaving aside economic cost considerations and individual site requirements.  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