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   1921篇
  免费   38篇
  国内免费   2篇
电工技术   60篇
综合类   1篇
化学工业   339篇
金属工艺   121篇
机械仪表   97篇
建筑科学   16篇
矿业工程   6篇
能源动力   13篇
轻工业   25篇
水利工程   17篇
石油天然气   77篇
无线电   170篇
一般工业技术   660篇
冶金工业   158篇
原子能技术   102篇
自动化技术   99篇
  2023年   28篇
  2022年   56篇
  2021年   55篇
  2020年   53篇
  2019年   48篇
  2018年   84篇
  2017年   59篇
  2016年   71篇
  2015年   51篇
  2014年   52篇
  2013年   104篇
  2012年   75篇
  2011年   81篇
  2010年   74篇
  2009年   67篇
  2008年   67篇
  2007年   78篇
  2006年   64篇
  2005年   46篇
  2004年   57篇
  2003年   42篇
  2002年   40篇
  2001年   32篇
  2000年   16篇
  1999年   16篇
  1998年   25篇
  1997年   19篇
  1996年   20篇
  1995年   13篇
  1991年   17篇
  1990年   20篇
  1989年   15篇
  1987年   17篇
  1986年   13篇
  1985年   20篇
  1983年   15篇
  1982年   15篇
  1981年   23篇
  1980年   27篇
  1979年   19篇
  1978年   13篇
  1977年   27篇
  1976年   28篇
  1975年   15篇
  1974年   20篇
  1973年   15篇
  1972年   19篇
  1971年   17篇
  1970年   11篇
  1966年   12篇
排序方式: 共有1961条查询结果,搜索用时 15 毫秒
1.
A layer-by-layer analysis of the structures, the phase compositions, and the defect substructures of differentially hardened rails has been carried by optical and transmission electron microscopy. It is found that the material volume of the rail head fillet is cooled faster than the volume located along the central axis.  相似文献   
2.
This paper considers thermochemical recuperation (TCR) of waste-heat using natural gas reforming by steam and combustion products. Combustion products contain steam (H2O), carbon dioxide (CO2), and ballast nitrogen (N2). Because endothermic chemical reactions take place, methane steam-dry reforming creates new synthetic fuel that contains valuable combustion components: hydrogen (H2), carbon monoxide (CO), and unreformed methane (CH4). There are several advantages to performing TCR in the industrial furnaces: high energy efficiency, high regeneration rate (rate of waste-heat recovery), and low emission of greenhouse gases (CO2, NOx). As will be shown, the use of TCR is significantly increasing the efficiency of industrial furnaces – it has been observed that TCR is capable of reducing fuel consumption by nearly 25%. Additionally, increased energy efficiency has a beneficial effect on the environment as it leads to a reduction in greenhouse gas emissions.  相似文献   
3.
In this paper, we consider the classical finite mixture model, which is an effective tool for modeling lifetime distributions for random samples from heterogeneous populations. We discuss new results on stochastic comparison for two finite mixtures when each of them is drawn from one of the following semiparametric families, i.e., proportional hazards, accelerated lifetime and proportional reversed hazards.  相似文献   
4.
5.
It is established that the capillary rise of a liquid has an oscillatory character, in contrast to the commonly accepted opinion that a vertical capillary is filled at a monotonically varying velocity. The value of the tangential shear stress arising in an ascending liquid is evaluated for ethyl alcohol and distilled water.  相似文献   
6.
The purpose and current construction status, at the Institute of Theoretical and Experimental Physics, of an experimental electronuclear setup, combining a pulsed proton linear accelerator (36 MeV, 0.5 mA) and a subcritical blanket thermal-power assembly 100 kW, are discussed. The main equipment is already available or is being built in industry. The setup can be used to investigate the dynamics of the interaction of a linac–driver and a subcritical reactor and problems concerning the accelerator–driver and the target–blanket assembly. The proton beams and neutron fluxes will be used for applied purposes. In the future it will be possible to increase substantially the current and energy of the proton beam.  相似文献   
7.
This article is devoted to work done in 2002–2006 as part of the unified project Reabilitatsiya to rehabilitate radiation hazardous objects and sections of the radioactively contaminated territory of the Russian Science Center Kurchatov Institute. The main objects of the rehabilitation work were old storage sites built for radioactive wastes on the territory of the Institute when military and civilian nuclear technologies were under development. The structural features of the storage sites, including the volumes and characteristics of the wastes stored, are presented. The salient aspects of the disposal sites, taken into account during the rehabilitation work, are discussed. The organization of the rehabilitation operations and the sequence in which they are performed, the special features of the technical design solutions used, the technological methods, and ways for conducting the work are described. __________ Translated from Atomnaya énergiya, Vol. 102, No. 5, pp. 300–306, May, 2007.  相似文献   
8.
The GaSe–Ga2Se3 system is studied by x-ray diffraction, electron microscopy, and differential scanning calorimetry. The results demonstrate that the nonadditivity of heat capacity observed near the eutectic composition after quenching is similar to the nonadditivity of properties in misfit layer compounds, which contain incommensurate structural components. The origin of this similarity is discussed in terms of the self-organization of interacting incommensurate elements in the melt and the formation of unstable suprastructural ensembles.  相似文献   
9.
The surface of a palladium-barium cathode was studied using scanning probe microscopy techniques. Data from the tunneling spectroscopy showed the pattern of the electron work function distribution over a microscopic region on the emitter surface. This pattern is compared to the distribution of various phases in the palladium-barium alloy employed.  相似文献   
10.
Introduction of the BER? KOMPAKS® automated system at the Vyksa Metallurgical Plant to safely and efficiently manage the operation of the plant’s equipment has allowed the facility to begin operating that equipment based on real-time evaluations of its actual physical condition. Introduction of the new system has also allowed better coordination of repair-scheduling with ongoing production operations, significantly improved the reliability and readiness of the equipment for operation at 100% capacity, completely eliminated the human factor from the process of monitoring the condition of equipment, and made it possible to check the quality and timeliness of equipment maintenance and repair work so as to ensure safe, efficient operation of the entire production complex.  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