全文获取类型
收费全文 | 74939篇 |
免费 | 707篇 |
国内免费 | 689篇 |
专业分类
电工技术 | 1458篇 |
综合类 | 47篇 |
化学工业 | 11177篇 |
金属工艺 | 3444篇 |
机械仪表 | 2638篇 |
建筑科学 | 1639篇 |
矿业工程 | 503篇 |
能源动力 | 1852篇 |
轻工业 | 6380篇 |
水利工程 | 845篇 |
石油天然气 | 2303篇 |
武器工业 | 41篇 |
无线电 | 7222篇 |
一般工业技术 | 16478篇 |
冶金工业 | 12458篇 |
原子能技术 | 2627篇 |
自动化技术 | 5223篇 |
出版年
2022年 | 573篇 |
2021年 | 904篇 |
2020年 | 697篇 |
2019年 | 777篇 |
2018年 | 1550篇 |
2017年 | 1562篇 |
2016年 | 1761篇 |
2015年 | 944篇 |
2014年 | 1556篇 |
2013年 | 3564篇 |
2012年 | 2360篇 |
2011年 | 2826篇 |
2010年 | 2371篇 |
2009年 | 2643篇 |
2008年 | 2620篇 |
2007年 | 2557篇 |
2006年 | 2185篇 |
2005年 | 1915篇 |
2004年 | 1841篇 |
2003年 | 1794篇 |
2002年 | 1707篇 |
2001年 | 1683篇 |
2000年 | 1675篇 |
1999年 | 1569篇 |
1998年 | 3687篇 |
1997年 | 2610篇 |
1996年 | 1946篇 |
1995年 | 1525篇 |
1994年 | 1331篇 |
1993年 | 1352篇 |
1992年 | 995篇 |
1991年 | 1050篇 |
1990年 | 1071篇 |
1989年 | 1052篇 |
1988年 | 942篇 |
1987年 | 875篇 |
1986年 | 879篇 |
1985年 | 935篇 |
1984年 | 781篇 |
1983年 | 769篇 |
1982年 | 677篇 |
1981年 | 689篇 |
1980年 | 665篇 |
1979年 | 649篇 |
1978年 | 627篇 |
1977年 | 777篇 |
1976年 | 934篇 |
1975年 | 581篇 |
1974年 | 553篇 |
1973年 | 546篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
61.
Yu. Dzyadykevych O. Smiyan 《International Journal of Refractory Metals and Hard Materials》2007,25(5-6):361-366
The results of investigation of initial stage of the tantalum borating as well as the effect of oxygen and hydrogen on it are presented. The scheme of the initial stage of tantalum boron saturation is proposed. 相似文献
62.
V. N. Kostyukov A. P. Naumenko V. A. Starikov A. A. Sinitsyn A. M. Volkov A. S. Rubanenko A. V. Rykin O. V. Kuznetsov 《Metallurgist》2007,51(11-12):596-604
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
63.
64.
O. A. Teplov I. G. Voropaev V. G. Dyubanov L. I. Leont’ev 《Russian Metallurgy (Metally)》2007,(4):268-275
The interaction of hydrogen with the zinc-containing electrometallurgical slime of the Severstal’ metallurgical works has been studied. The sequence of transformations in the slime heated to 1100°C in hydrogen or air has been established. The experimental and calculated weight losses coincide. Some of the carbonates are shown to decompose in the temperature range 300–700°C, and most iron and zinc oxides are reduced to a metal. In the temperature range 650–850°C, zinc is almost completely sublimated. At temperatures above 800°C, complex oxides are reduced and calcium and magnesium carbonates and sulfates are likely to decompose. Experimental digital data on the zinc sublimation rate are processed by the least squares method with approximating equations used in thermal analysis. The kinetics of nonisothermal zinc sublimation is comprehensively analyzed using a unique procedure developed for taking into account the background of a peak and the effect of accompanying processes. An equation for the calculation of the zinc sublimation rate under experimental conditions (fluidized bed) is given and tested. 相似文献
65.
66.
Present-day worldwide water problems require new management tools and sustainable system innovations. At Delft University of Technology research is being carried out into water resources and management development aimed at forming such tools and innovations, focused on Integrated River Basin Management (IRBM). One of the case-studies deals with Dutch water management and technology in the context of European IRBM in the form of the 2000 Water Frame Directive. The Netherlands experience many water problems and European IRBM could bring help by offering a framework for both international cooperation and technological innovations. To work as an adequate management tool European IRBM should be tailored to the Dutch water tradition, which recently culminated in Integrated Water Management. Both approaches are in some respects contradicting. Europe pursues, for example, centralized control; while the Dutch have their strongly water boards based decentralized administration. The tensions between both approaches require mutual adaptation, for which the concept of subsidiarity might offer points of departure. This paper describes the first results of the case-research into Dutch water management and technology in the context of Europe as well as the backgrounds and the set-up of the research as a whole. 相似文献
67.
In this study, the effects of the phosphonic acid based sequestering agent EDTMPA used in the textile dye baths on colour and organic matter removal by ozone oxidation was experimentally investigated. Procion Navy HEXL dyestuff that has been commonly used for the reactive dyeing of cellulose fibers was selected as the model component. The organic matter oxidation by ozone was determined to obey the pseudo-first order kinetics as they are treated singly or in combination. COD removal rates obtained from pseudo-first order reaction kinetics showed that oxidation of Navy HEXL alone (0.0947 L/min) was faster than that of EDTMPA (0.0171 L/min) and EDTMPA with dye (0.0155 L/min) at pH 3.0. It was also found that reaction rates of single EDTMPA removal and EDTMPA and dye mixture removal increased as the reaction pH was increased from 3.0 to 10.5. 相似文献
68.
A. O. Skomorokhov V. N. Kutinsky M. T. Slepov 《Pattern Recognition and Image Analysis》2006,16(1):85-88
The paper describes a few modifications of the classification tree construction algorithm that have proved to be useful for
solving tasks of noise spectra processing with reference to NPP diagnostics.
The article was translated by the authors. 相似文献
69.
A method for measuring the characteristics of tunneling and impact ionization in thin-film electroluminescent emitters is suggested. This method makes it possible to find time dependences of the space-charge layer thickness near the anode and the length of the impact ionization region, to determine more exactly the time dependence of the field in the potential barrier at the cathode interface, the maximum depth of the surface states from which electron tunneling occurs, the minimum thickness of the barrier, and the electron tunneling probability, as well as the impact ionization rate for the deep centers related to structural defects of the phosphor layer. 相似文献
70.
We introduce functions for relative maximization in a general context: the beta and alpha applications. After a systematic study of different kinds of regularities, we investigate how to approximate certain values of these functions using periodic orbits. We also show that the differential of an alpha application determines the asymptotic behavior of the optimal trajectories. 相似文献