全文获取类型
收费全文 | 41004篇 |
免费 | 5212篇 |
国内免费 | 1404篇 |
专业分类
电工技术 | 16331篇 |
综合类 | 3033篇 |
化学工业 | 1723篇 |
金属工艺 | 1414篇 |
机械仪表 | 2717篇 |
建筑科学 | 2419篇 |
矿业工程 | 565篇 |
能源动力 | 7845篇 |
轻工业 | 363篇 |
水利工程 | 1785篇 |
石油天然气 | 919篇 |
武器工业 | 386篇 |
无线电 | 1839篇 |
一般工业技术 | 2017篇 |
冶金工业 | 889篇 |
原子能技术 | 624篇 |
自动化技术 | 2751篇 |
出版年
2024年 | 264篇 |
2023年 | 666篇 |
2022年 | 1274篇 |
2021年 | 1368篇 |
2020年 | 1467篇 |
2019年 | 1135篇 |
2018年 | 1065篇 |
2017年 | 1398篇 |
2016年 | 1704篇 |
2015年 | 1831篇 |
2014年 | 3114篇 |
2013年 | 2391篇 |
2012年 | 3379篇 |
2011年 | 3626篇 |
2010年 | 2466篇 |
2009年 | 2519篇 |
2008年 | 2251篇 |
2007年 | 2607篇 |
2006年 | 2315篇 |
2005年 | 1815篇 |
2004年 | 1441篇 |
2003年 | 1338篇 |
2002年 | 1073篇 |
2001年 | 984篇 |
2000年 | 861篇 |
1999年 | 661篇 |
1998年 | 437篇 |
1997年 | 388篇 |
1996年 | 338篇 |
1995年 | 298篇 |
1994年 | 218篇 |
1993年 | 195篇 |
1992年 | 161篇 |
1991年 | 125篇 |
1990年 | 94篇 |
1989年 | 95篇 |
1988年 | 53篇 |
1987年 | 41篇 |
1986年 | 22篇 |
1985年 | 26篇 |
1984年 | 40篇 |
1983年 | 10篇 |
1982年 | 21篇 |
1981年 | 10篇 |
1980年 | 12篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1966年 | 2篇 |
1959年 | 4篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
N. N. Man’kina A. V. Kirilina O. V. Ovechkina B. G. Lyudomirskii B. G. Rubanov Yu. G. Tikhomirov T. Sh. Zakirov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2006,40(5):307-315
Studies conducted on two power-generating units at the Kharanorskaya SAPP relative to the steam-water-oxygen passivation,
preservation, and partial cleaning of all boiler-heating surfaces, including the surfaces of the reheater, and passivation
of the surfaces of the high-pressure heaters on the steam and water sides by the steam-oxygen method, as well as partial passivation,
preservation, and cleaning of turbine blading are presented.
__________
Translated from élektricheskie Stantsii, No. 6, pp. 56–64, May, 2006. 相似文献
42.
The scope of the paper is the assessment of the technical risk involved in long-term operation of power units. Detailed analyses have been conducted for steam turbine components. The sources and consequences of risk have been identified and the probability of turbine components failure calculated. The quantitative assessment of the risk has been made and possibilities of its reduction discussed. 相似文献
43.
简述了上海汽轮机有限公司(STC)与西门子公司首次合作制造的目前国内最大容量的外高桥900MW超临界机组的一些基本情况,介绍了在合作制造中为保证生产进度和质量而采取的工艺改进、技术攻关等措施,以及通过合作制造提升了我公司的制造能力和管理水平。 相似文献
44.
介绍了WOODWARD505电液控制器原理、功能及在包钢热电厂汽轮鼓风机控制系统的成功应用,大大改善了汽轮机的调节控制品质。 相似文献
45.
Ralph W. Pridmore 《Color research and application》2008,33(1):77-81
In present convention, chromatic induction (simultaneous and successive contrast) is usually held to be an opponent color process. Fifty years ago, it was an accepted complementary color process. The latter was never disputed yet apparently overlooked, and is here shown to be the more accurate account by inspecting afterimages and published data on simultaneous and successive hue induction. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 77–81, 2008 相似文献
46.
The architects and builders in the past lacked our knowledge concerning fluid dynamics, but they exhibited a deep rooted ability to observe and reflect - thus, different cultures have developed by trial and error. The authors have produced a stimulating analysis which couples the science of fluid dynamics and a sensitive understanding of past cultures. The paper is recommended reading. 相似文献
47.
通过力学性能评估和金相组织观察,研究五种热处理制度,两个周期的试验结果,确定了K418B合金细晶铸造整体涡轮的真空热处理工艺。 相似文献
48.
49.
Heat-shock induction of heat-shock protein genes is due to a specific promoter element (the heat-shock element, HSE). This study used lacZ under HSE control (HSE-lacZ) to characterize HSE activity in Saccharomyces cerevisiae cells of different physiological states and differing genetic backgrounds. In batch fermentations HSE-lacZ induction by heat shock was maximal in exponential growth, and showed marked decline with the approach to stationary phase. Expression in the absence of heat shock was unaffected by growth phase, indicating that the growth-dependent expression of many yeast heat-shock genes uses promoter elements in addition to the HSE. Heat-induced expression was strongly influenced by the temperature at which cultures were grown. While basal, uninduced expression was constant during growth at different temperatures to 30 degrees C, induction by transfer to 39 degrees C was reduced by increases in growth temperature as low as 18-24 degrees C. Maximal HSE-lacZ induction (30- to 50-fold) was in cultures grown at low temperatures (18-24 degrees C), then heat shocked at 39 degrees C. Ethanol was a poor inducer. Mutations having little effect on HSE-lacZ expression included a respiratory petite; ubi4 (which inactivates the poly-ubiquitin gene); also ubc4 and ubc5 (which each inactivate one of the ubiquitin ligases involved in degradation of aberrant protein). pep4-3 increased both basal and induced beta-galactosidase about two-fold, probably because of slower turnover of this enzyme in pep4-3 strains. 相似文献
50.
从ZnO电阻的非线性特性出发,对采用ZnO作为灭磁电阻时阀片的均流/均能进行理论论述,指出阀片均能性能的好坏主要依赖于阀片自身的特性;分析比较了ZnO阀片的不同选择方法对均流/均能的影响,指出阀片的均流/均能很大程度上取决于可供选择的阀片的库存量.该研究为发电机励磁系统的安全稳定运行提供了有力的保证. 相似文献