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   111篇
  免费   2篇
  国内免费   1篇
化学工业   17篇
金属工艺   2篇
机械仪表   13篇
建筑科学   1篇
能源动力   4篇
轻工业   2篇
无线电   9篇
一般工业技术   40篇
冶金工业   18篇
自动化技术   8篇
  2020年   3篇
  2018年   1篇
  2017年   2篇
  2016年   1篇
  2015年   3篇
  2014年   3篇
  2013年   12篇
  2012年   10篇
  2010年   5篇
  2009年   4篇
  2008年   6篇
  2007年   4篇
  2006年   7篇
  2005年   5篇
  2004年   3篇
  2002年   5篇
  2001年   2篇
  2000年   1篇
  1999年   1篇
  1998年   5篇
  1997年   3篇
  1996年   4篇
  1995年   1篇
  1994年   2篇
  1993年   5篇
  1992年   1篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1983年   2篇
  1982年   1篇
  1977年   1篇
  1976年   2篇
  1972年   1篇
排序方式: 共有114条查询结果,搜索用时 46 毫秒
1.
Privatisation has been part of Israeli housing policy since the first public housing units were built in 1949. It has involved the sale of publicly‐owned dwellings to sitting tenants, but also the shift to residents of responsibilities usually associated with ownership, such as maintenance and tax liabilities. The evolution of this policy is examined by considering the social, economic and political factors which have shaped the development of Israeli public housing policy from its beginning.  相似文献   
2.
3.
Sodium ion batteries (SIBs) are considered as a promising alternative to threaten the reign of lithium ion batteries (LIBs) among various next-generation rechargeable energy storage systems, including magnesium ion, metal air, and metal sulfur batteries. Since both sodium and lithium are located in Group 1 of the periodic table, they share similar (electro)chemical properties with regard to ionization pattern, electronegativity, and electronic configuration; thus the vast number of compounds developed from LIBs can provide guidance to design electrode materials for SIBs. However, the larger ionic radius of the sodium cation and unique (de)sodiation processes may also lead to uncertainties in terms of thermodynamic or kinetic properties. Herein, we present the first construction of SIBs based on inorganic fullerene-like (IF) MoS2 nanoparticles. Closed-shell-type structures, represented by C60 fullerene, have largely been neglected for studies of alkali-metal hosting materials due to their inaccessibility for intercalating ions into the inner spaces. However, IF-MoS2, with faceted surfaces, can diffuse sodium ions through the defective channels, thereby allowing reversible sodium ion intercalation/deintercalation. Interestingly, Re-doped MoS2 showed good electrochemical performances with fast kinetics (ca. 74 mA h g−1 at 20 C). N-type doping caused by Re substitution of Mo in IF-MoS2 revealed enhanced electrical conductivity and an increased number of diffusion defect sites. Thus, chemical modification of fullerene-like structures through doping is proven to be a promising synthetic strategy to prepare improved electrodes.  相似文献   
4.
5.
Nanoparticles of various layered compounds having a closed cage or nanotubular structure, designated also inorganic fullerene-like (IF) materials, have been reported in the past. In this work IF-CdCl2 nanoparticles were synthesized by two methods. In one technique, a high temperature evaporation and subsequent condensation of dried cadmium chloride powder was used. In the other method, electron beam irradiation of the source powder led to its recrystallization into closed nanoparticles with a nonhollow core. The two methods are shown to produce nanoparticles of different topologies. While mostly spherical nested structures are obtained from the high temperature process, polyhedra with hexagonal or elongated rectangular characters are obtained by the electron beam induced process. The analysis also shows that, while the source (dried) powder is orthorhombic cadmium chloride monohydrate, the crystallized IF cage consists of the anhydrous 3R polytype which is not stable as bulk material in ambient atmosphere. Consistent with previous observations, this study shows that the seamless structure of the IF materials can stabilize phases, which are otherwise unstable in ambient conditions.  相似文献   
6.
Results on electron field emission from free standing tungsten disulfide (WS2) nanotubes (NTs) are presented. Experiments show that the NTs protruding on top of microstructures are efficient cold emitters with turn‐on fields as low as 1 V/μm and field enhancement of few thousands. Furthermore, the emission current shows remarkable stability over more than eighteen hours of continuous operation. Such performance and long‐term stability of the WS2 cathodes is comparable to that reported for optimized carbon nanotube (CNTs) based emitters. Besides this, it is found that the WS2 cathodes prepared are less sensitive than CNTs in chemical reactive ambients. The high field enhancement and superior reliability achieved indicates a potential for vacuum nanoelectronics and flat panel display applications.  相似文献   
7.
Abstract

Modern engineering design often relies on computer simulations to evaluate candidate designs, a scenario which results in an optimization of a computationally expensive black-box function. In these settings, there will often exist candidate designs which cause the simulation to fail, and can therefore degrade the search effectiveness. To address this issue, this paper proposes a new metamodel-assisted computational intelligence optimization algorithm which incorporates classifiers into the optimization search. The classifiers predict which candidate designs are expected to cause the simulation to fail, and this prediction is used to bias the search towards designs predicted to be valid. To enhance the search effectiveness, the proposed algorithm uses an ensemble approach which concurrently employs several metamodels and classifiers. A rigorous performance analysis based on a set of simulation-driven design optimization problems shows the effectiveness of the proposed algorithm.  相似文献   
8.
9.
10.
Recreational SCUBA diving exposes individuals to environmental stresses not often encountered in other types of activity. These stresses include increased ambient pressure, raised partial pressure of O(2), increased resistance to movement, added weight and drag of diving equipment, cold stress, and a higher breathing resistance. One means to understand how such stresses affect a diver is to employ the stress-strain-adaptive response model. Physiologic adaptations, like an increase in VO(2) in response to cold stress, will minimize the strain placed on thermal balance. Nonphysiologic adaptive responses include those behavioral and equipment interventions that isolate the diver from a particular stress. Self-contained underwater breathing apparatus (SCUBA) isolates the diver from the inability to extract O(2) from the water; dive garments minimize the stress of cold water immersion. This review will focus on cardiorespiratory and thermal responses to SCUBA diving, using the stress-strain-adaptive response model to illustrate the interaction between diver and environment. Some responses like hyperventilation, cardiac arrhythmias, or cold injury due to vasoconstriction are not considered adaptive but are realistic possibilities in diving environments.  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