全文获取类型
收费全文 | 527篇 |
免费 | 22篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 43篇 |
金属工艺 | 29篇 |
机械仪表 | 27篇 |
建筑科学 | 4篇 |
矿业工程 | 6篇 |
能源动力 | 2篇 |
轻工业 | 2篇 |
水利工程 | 3篇 |
石油天然气 | 56篇 |
无线电 | 54篇 |
一般工业技术 | 219篇 |
冶金工业 | 46篇 |
原子能技术 | 26篇 |
自动化技术 | 27篇 |
出版年
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 22篇 |
2015年 | 16篇 |
2014年 | 20篇 |
2013年 | 16篇 |
2012年 | 30篇 |
2011年 | 28篇 |
2010年 | 21篇 |
2009年 | 18篇 |
2008年 | 14篇 |
2007年 | 15篇 |
2006年 | 19篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1996年 | 4篇 |
1994年 | 6篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 4篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1974年 | 11篇 |
1973年 | 7篇 |
1972年 | 14篇 |
1970年 | 6篇 |
1968年 | 8篇 |
1967年 | 8篇 |
1966年 | 11篇 |
1957年 | 5篇 |
排序方式: 共有549条查询结果,搜索用时 875 毫秒
1.
Broadband chaotic oscillations were monitored in a depressed potential collector of a traveling-wave oscillator (TWO). This signal appears due to the oscillations of a virtual cathode, which is formed in the spent electron beam under the action of retarding fields existing in the multistage depressed collector. 相似文献
2.
A. P. Vasil’ev V. P. Vasyukhno M. E. Netecha V. L. Vysotskii R. I. Kalinin A. A. Sarkisov A. Yu. Kazennov Yu. V. Sivintsev A. M. Chernyaev 《Atomic Energy》2006,101(1):506-511
The radioecological conditions which developed on the territory over the long operating time of the object of the naval fleet
in Guba Andreev are described. The results of an analysis of the sources of the real and potential danger and measures to
prevent dangerous effects for the environment and the workers at the time remediation work is performed are discussed.
__________
Translated from Atomnaya énergiya, Vol. 101, No. 1, pp. 49–55, July, 2006. 相似文献
3.
V. V. Vavilova V. M. Ievlev A. P. Isaenko Yu. E. Kalinin Yu. K. Kovneristyi N. A. Palii B. G. Sukhodolov V. N. Timofeev 《Inorganic Materials》2003,39(1):72-76
The effect of pulsed photon annealing with energy densities from 1.4 to 42 J/cm2 for various lengths of time on the structure of the amorphous alloy Fe79P14.2Si4.4Mn2.2V0.2 was studied by x-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The results demonstrate that short-term irradiation with low energy densities leads to surface relaxation of the amorphous alloy, increases the strength of the surface layer, and reduces the internal-friction peak. Longer term photon annealing leads to crystallization of the alloy throughout the sample thickness. 相似文献
4.
The effect of an external harmonic signal on the characteristics of microwave generation in a non-relativistic electron beam with virtual cathode (VC) formed in a static retarding electric field (low-voltage vircator system) has been experimentally studied. A significant increase in the vircator generation power is observed when the frequency of the external signal is close to the frequency of VC oscillations. At large detunings, a broadband chaotic generation is observed. 相似文献
5.
E. N. Egorov Yu. A. Kalinin A. A. Koronovskii Yu. I. Levin A. E. Hramov 《Journal of Communications Technology and Electronics》2007,52(1):45-57
A nonrelativistic electron beam with a virtual cathode situated in the diode gap with a decelerating field is experimentally and theoretically studied. A 1D model of the electron beam in the presence of a decelerating field is constructed. Nonlinear nonstationary processes in this system are investigated by means of numerical analysis of the model. The processes are described and interpreted with regard to formation and interaction of structures in the electron flow. The theoretical results are qualitatively confirmed by the experimental data showing that the system under study can be considered as a promising controlled source of chaotic oscillations in the microwave range. 相似文献
6.
For the system with a small parameter under nonlinearities, consideration was given to the problem of optimal speed. The values of the multivariable control actions are bounded in the Euclidean norm. The theorem of existence and asymptotic properties of the solution of this problem was proved. It underlies the algorithm to construct asymptotic arbitrary-order approximations to the optimal control. 相似文献
7.
Conclusions Experiments have confirmed the validity of Eq. (1) and hence the correctness of the method of investigating the sinteringkinetics of spheroidized particles based on electrical conductivity measurements. In the temperature range investigated single-crystalline nickel oxide sinters better in argon than in air, but the mechanisms of mass transfer and energies of activation in both cases are virtually identical. In both gases the kinetic dependence of the initial stage of sintering was found to be of the form x3
R t.Translated from Poroshkovaya Metallurgiya, No. 2(266), pp. 32–35, February, 1985. 相似文献
8.
Based on long-term tests of aluminum alloys in seawater of various climatic zones from the Arctic to the tropics, the peculiarities of their corrosion behavior are revealed. In contrast to other alloys, hydrogen sulfide has a beneficial effect on their corrosion resistance due to the passivation. However, deep in the Black Sea, the alloys, which are susceptible to structural types of corrosion, were subjected to strong exfoliation corrosion, because hydrogen sulfide excluded fouling with microorganisms that inhibits exfoliation corrosion. Alloys of the Al-Mg system exhibit the highest corrosion resistance in seawater. Alloy of an AMr61 type (σul = 340 MPa, σ0.2 = 180–210 MPa, δ = 11–15%) has shown a good performance. Alloying with scandium and thermomechanical treatment make possible further simultaneous improvement of mechanical properties and corrosion resistance. It is shown that crevice corrosion is more typical of corrosion-resistant low aluminum alloys possessing lower free-corrosion and pitting potentials compared to high alloys, which are susceptible to structural types of corrosion, in particular, exfoliation corrosion. The methods of the aluminum alloys protection against marine corrosion are considered. It is shown that, in contrast to carbon steels, the anodic-cathodic protection is used for aluminum alloys.__________Translated from Zashchita Metallov, Vol. 41, No. 4, 2005, pp. 347–359.Original Russian Text Copyright © 2005 by Sinyavskii, Kalinin. 相似文献
9.
V. Ya. Abramov S. N. Bozin O. I. Eliseeva G. M. Kalinin V. I. Kalyandruk E. M. Lyutyi 《Materials Science》1995,30(4):465-469
The effect of liquid-metal embrittlement in lead melt is typical of Kh12MVSFBR ferrite-martensitic steel and is observed in the temperature range of 300 – 500°C at a deformation rate of 8 · 10–4 sec–1. The maximum decrease in the plasticity of tempered specimens occurs at a temperature of 450°C. A decrease in the amount of -ferrite in the composition (martensite hardening without high-temperature annealing) results in a substantial decrease in plasticity and in broadening of the temperature range of embrittlement. 08Kh16N11S3MB austenitic steel is not affected by liquid metal embrittlement in the investigated temperature range for the deformation rates under consideration.Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 30, No. 4, pp. 71–76, July – August, 1994. 相似文献
10.
Costa Fraga RA Kalinin A Kühnel M Hochhaus DC Schottelius A Polz J Kaluza MC Neumayer P Grisenti RE 《The Review of scientific instruments》2012,83(2):025102
We present a cryogenic source of periodic streams of micrometer-sized hydrogen and argon droplets as ideal mass-limited target systems for fundamental intense laser-driven plasma applications. The highly compact design combined with a high temporal and spatial droplet stability makes our injector ideally suited for experiments using state-of-the-art high-power lasers in which a precise synchronization between the laser pulses and the droplets is mandatory. We show this by irradiating argon droplets with multi-terawatt pulses. 相似文献