全文获取类型
收费全文 | 31265篇 |
免费 | 2480篇 |
国内免费 | 847篇 |
专业分类
电工技术 | 5925篇 |
综合类 | 2062篇 |
化学工业 | 3153篇 |
金属工艺 | 1390篇 |
机械仪表 | 2446篇 |
建筑科学 | 1957篇 |
矿业工程 | 636篇 |
能源动力 | 6952篇 |
轻工业 | 1001篇 |
水利工程 | 1407篇 |
石油天然气 | 1860篇 |
武器工业 | 165篇 |
无线电 | 578篇 |
一般工业技术 | 2282篇 |
冶金工业 | 1014篇 |
原子能技术 | 563篇 |
自动化技术 | 1201篇 |
出版年
2024年 | 140篇 |
2023年 | 413篇 |
2022年 | 757篇 |
2021年 | 868篇 |
2020年 | 889篇 |
2019年 | 697篇 |
2018年 | 620篇 |
2017年 | 776篇 |
2016年 | 927篇 |
2015年 | 1058篇 |
2014年 | 2164篇 |
2013年 | 1791篇 |
2012年 | 2303篇 |
2011年 | 2508篇 |
2010年 | 1744篇 |
2009年 | 1763篇 |
2008年 | 1585篇 |
2007年 | 2046篇 |
2006年 | 1939篇 |
2005年 | 1530篇 |
2004年 | 1324篇 |
2003年 | 1208篇 |
2002年 | 1001篇 |
2001年 | 864篇 |
2000年 | 781篇 |
1999年 | 617篇 |
1998年 | 431篇 |
1997年 | 348篇 |
1996年 | 314篇 |
1995年 | 274篇 |
1994年 | 214篇 |
1993年 | 134篇 |
1992年 | 124篇 |
1991年 | 97篇 |
1990年 | 84篇 |
1989年 | 77篇 |
1988年 | 57篇 |
1987年 | 36篇 |
1986年 | 13篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 10篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1961年 | 2篇 |
1959年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The paper shows that an analytical evaluation of the power coefficient Cp for an ideal horizontal-axis wind turbine can be made via an expression giving the direct relationship of Cp and the axial induction factor a. The results obtained agree closely with those obtained numerically from the usual integral expression involving several variables. 相似文献
52.
Safe and Economic Operation of Power Plants – Research Results in the Field of Materials, Design and Maintenance Components of power plants which undergo high temperatures are subjected to complex loading situations. The requirements on the used materials result from the special operation conditions of the plants and have to be adjusted to the steadily growing requirements on higher efficiency of the complete power plant as well as to those of safe and economic operation. The expenses for control and downtimes are directly connected with economic efficiency and availability. However, in case of new procedures or components it is not possible to revert to the existing know‐how. Different failure mechanisms than known before can occur. The same goes for the load situation. Therefore the knowledge base has to be extended to in‐advance or even parallely running scientific examinations that life assessment and maintenance strategies can be applied which guarantee the operational reliability and the efficiency of the plant. The main emphasis of these F&E works has to be put on condition monitoring based on actual operational data, the standard materials’ and component’s behaviour (deformation, damage and failure behaviour) in connection with design of components and the related material laws. In the framework of applied AVIF projects, following problems are handled:. – qualification of materials by determinating parameters related to practise. – optimal design of components by making available material laws and numerical tools. – economic manufacturing of components by qualifying processing methods such as welding. – The results can be transferred to concepts for safe and economic operation of power plants, especially for newly introduced materials for which there is no operational experience available. 相似文献
53.
Reliability evaluation and optimisation of imperfect inspections for a component with multi-defects 总被引:1,自引:1,他引:0
Jianmin Zhao A.H.C. Chan C. Roberts K.B. Madelin 《Reliability Engineering & System Safety》2007,92(1):65-73
In this paper, a model is developed to evaluate the reliability and optimise the inspection schedule for a multi-defect component. The model uses a non-homogeneous Poisson process (NHPP) method in conjunction with a delay time approach. The inspections are designed to detect any defects in the component, however it can be imperfect. The defect is a definable state before a functional failure happens to the component. Occurrences of defects are assumed to follow an NHPP and a defect will be minimally repaired if it is identified during an inspection. It is shown that the failures occurring in an interval of inspection will also follow an NHPP. The situation of imperfect inspections and non-constant inspection intervals are considered. An algorithm is presented to optimise the intervals of inspections in order to maximise the reliability of the component, and the properties of the algorithm are shown. A numerical example with parametric study is given to show the performance of the model and the algorithm. 相似文献
54.
稠油热采注汽管道由于长期在高温、高压下运行,极易发生各种损伤,如腐蚀、裂纹、材料退化等,极易造成管道承压能力降低,发生失效事故。如何检测出潜在危险性缺陷,判断注汽管道能否继续使用,是保证注汽管道安全运行的关键问题。探讨了高温压力管道在线检测技术发展现状及其应用范围。 相似文献
55.
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
56.
57.
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
58.
Influence of electroosmotic treatment on the hydro-mechanical behaviour of clayey silts: preliminary experimental results 总被引:1,自引:0,他引:1
Laura Gabrieli Cristina Jommi Guido Musso Enrique Romero 《Journal of Applied Electrochemistry》2008,38(7):1043-1051
Preliminary results of an investigation focused on the influence of electrokinetic treatment on the mechanical and hydraulic
behaviour of clayey soils are presented. The experimental programme aims at providing a contribution to the sustainability
of contaminant extraction or containment via electroosmosis. Changes in the hydraulic and mechanical properties of two illitic
clayey soils, subjected to a DC electric field, were investigated. Samples of the two soils were subjected to electrokinetic
filtration, for different periods of time, and under different constant loads. Afterwards, they were tested under one-dimensional
compression to detect changes in stiffness and hydraulic conductivity due to the electrical treatment. After the application
of a DC field for a few hours, a small reversible increment in the average soil stiffness was observed, with respect to the
untreated soil, while the hydraulic conductivity was not affected substantially. Dramatic changes of the mechanical and hydraulic
soil properties, correlated to changes of the soil pH, were observed following non-conditioned electrokinetic treatment with
duration of the order of days. 相似文献
59.
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
60.
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