全文获取类型
收费全文 | 12286篇 |
免费 | 620篇 |
国内免费 | 258篇 |
专业分类
电工技术 | 1658篇 |
技术理论 | 1篇 |
综合类 | 434篇 |
化学工业 | 516篇 |
金属工艺 | 708篇 |
机械仪表 | 1605篇 |
建筑科学 | 981篇 |
矿业工程 | 276篇 |
能源动力 | 1578篇 |
轻工业 | 181篇 |
水利工程 | 74篇 |
石油天然气 | 553篇 |
武器工业 | 158篇 |
无线电 | 806篇 |
一般工业技术 | 509篇 |
冶金工业 | 294篇 |
原子能技术 | 101篇 |
自动化技术 | 2731篇 |
出版年
2024年 | 30篇 |
2023年 | 141篇 |
2022年 | 217篇 |
2021年 | 287篇 |
2020年 | 320篇 |
2019年 | 259篇 |
2018年 | 193篇 |
2017年 | 347篇 |
2016年 | 499篇 |
2015年 | 455篇 |
2014年 | 692篇 |
2013年 | 573篇 |
2012年 | 668篇 |
2011年 | 993篇 |
2010年 | 694篇 |
2009年 | 712篇 |
2008年 | 568篇 |
2007年 | 759篇 |
2006年 | 690篇 |
2005年 | 648篇 |
2004年 | 566篇 |
2003年 | 536篇 |
2002年 | 386篇 |
2001年 | 287篇 |
2000年 | 280篇 |
1999年 | 263篇 |
1998年 | 226篇 |
1997年 | 198篇 |
1996年 | 147篇 |
1995年 | 136篇 |
1994年 | 86篇 |
1993年 | 66篇 |
1992年 | 54篇 |
1991年 | 39篇 |
1990年 | 27篇 |
1989年 | 39篇 |
1988年 | 19篇 |
1987年 | 7篇 |
1986年 | 16篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
51.
近年来各行各业加强职业道德建设,取得了一定成绩,涌现了一大批敬业爱岗、服务社会的岗位明星,但也存在着这样或那样的认识误区或现实局限,如形式主义、短期行为和领导观念异位等,这极大地阻碍了职业道德建设的深入推进。职业道德建设就其特征而言,它具有长期性、时代性和阶级性、相对稳定性以及创新性等属性,对此需要有一个理智而清晰的认识。应从营造良好的社会氛围、制定切实可行的道德准则、进行规范化的教育引导和发挥先进人物的示范作用等几方面入手,把职业道德建设推向深入。 相似文献
52.
Allen M. Johnson Michael A. Schoenfelder David J. Lebold 《Quality and Reliability Engineering International》1993,9(1):55-62
The Rainbow net simulation technique is applied to modelling the impact of system load and fault handling on the availability of a fault-tolerant multiprocessor architecture. Rainbow nets are described along with the motivation for creating this modelling technique. A Rainbow net fault-handling model is created for the fault-tolerant multiprocessor architecture and the topology is shown to remain constant in size, independent of the number of processor, memory and I/O elements configured in the system. Simulation is performed with a varying load in terms of the number of active jobs the system must support. Results are given showing how the fault-tolerant capability varies with load. Two new metrics for evaluating fault tolerance are introduced; namely full fault-tolerability and partial fault-tolerability. They are based on simple observations in the model. 相似文献
53.
54.
55.
56.
In this article, results are presented of annual simulations of a decentralized (regional) plant for the power and heat supply of a residential complex. This complex consists of four houses with 40 flats all in all. The annual power consumption of the complex is 157 MWh and the heat requirement is 325 MWh. The concrete dynamics of the energy demands over the year is taken into consideration. The energy supply system is composed of a power-controlled combined heat and power (CHP) plant (55 kW), a photovoltaic plant (PV array or PV plant) array for power generation as well as a field of solar thermal collectors with a short-term accumulator for water heating and a long-term accumulator for supplying heat for domestic heating purposes. Simulation results demonstrate that synergetic effects result from the combination of a CHP plant with wind power and PV plants of varying sizes, which have an effect on the cost effectiveness of the plant as a whole with the different dynamics of energy sources (wind and solar energies) and of the consumption of power and heat being the decisive factors. The power deficits of wind power and PV plants are compensated through the application of a natural gas-operated CHP plant. In almost all variants, the demand for fossil energy carriers is distinctly less than in conventional energy supply plants. 相似文献
57.
We present the fabrication and short circuit test results of a 14 kV single-phase resistive superconducting fault current limiter (SFCL) based on YBa2Cu3O7 (YBCO) films. Individual components were processed using the 4″ YBCO films and have the rated voltage and current of 600 V and 35 A at 77 K, respectively. Twenty four components, eight components in series and three lines in parallel, make a module having the rated voltage and current of 4.8 kV and 105 A, respectively. Three modules were assembled in series to produce the SFCL working at 77 K, a 14 kV single-phase machine for the 22.9 kV Y-Y grid. short circuit tests were successfully conducted in an accredited test facility with the maximum fault currents up to 14.1 kAP. All components quenched together upon faults and shared the rated voltage evenly without any supplementary device between the modules. This proves that the SFCL based on YBCO films may not only work reliably at 22.9 kV, but also provide technical feasibility for higher voltage application including the transmission grids. 相似文献
58.
Renewable energy systems: A societal and technological platform 总被引:1,自引:0,他引:1
Today, the analysis of renewable energy places the emphasis on the technological and economic attributes with social and environmental impact assessment providing for a rather static, narrow frame of analysis. The participation and response of social actors and other stakeholders is usually of a traditional type, with consultation documents and public meetings, collection of complaints and suggestion schemes. This often encourages parochialism and an over-concentration on relatively trivial issues. It is, therefore, imperative to establish a new participatory planning platform to incorporate the wider socio-economic aspects of renewable energy systems and to provide for an operational analytical decomposition of them. In this work the issue of decomposition analysis is clarified, and a new agenda for the societal and technological decomposition analysis of renewable energy systems is developed. A case study is disclosed to present the relevance of the established platform for integrated (renewable) energy systems planning. Innovative aspects comprise of the simultaneous inclusion of decision analysis and social acceptance methods and tools in concert with the related public participation techniques. 相似文献
59.
60.
经过143年的发展,世界石化工业已趋于成熟并成为全球最大的传统基础产业。目前全球石油化工工业发展呈现出以下新特点:一是世界石化工业形成美亚欧三足鼎立格局,亚太在三足中的地位将进一步提升;二是以中国为代表的发展中国家的石化工业正在进一步崛起;三是世界石化产业的集中度越来越高;四是新一轮兼并联合改变了全球石油石化业界的部分格局。 相似文献