全文获取类型
收费全文 | 758篇 |
免费 | 10篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 207篇 |
金属工艺 | 105篇 |
机械仪表 | 11篇 |
建筑科学 | 7篇 |
矿业工程 | 10篇 |
能源动力 | 1篇 |
轻工业 | 47篇 |
水利工程 | 7篇 |
石油天然气 | 63篇 |
无线电 | 29篇 |
一般工业技术 | 103篇 |
冶金工业 | 138篇 |
原子能技术 | 13篇 |
自动化技术 | 24篇 |
出版年
2021年 | 12篇 |
2019年 | 18篇 |
2018年 | 22篇 |
2017年 | 22篇 |
2016年 | 29篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 19篇 |
2012年 | 12篇 |
2011年 | 30篇 |
2010年 | 26篇 |
2009年 | 19篇 |
2008年 | 18篇 |
2007年 | 23篇 |
2006年 | 12篇 |
2005年 | 25篇 |
2004年 | 13篇 |
2003年 | 17篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1998年 | 19篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 15篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 13篇 |
1983年 | 10篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1979年 | 8篇 |
1978年 | 16篇 |
1977年 | 17篇 |
1976年 | 24篇 |
1975年 | 12篇 |
1974年 | 16篇 |
1973年 | 7篇 |
1972年 | 15篇 |
1971年 | 9篇 |
1968年 | 9篇 |
1967年 | 8篇 |
1966年 | 8篇 |
排序方式: 共有768条查询结果,搜索用时 31 毫秒
1.
The paper concerns an analysis of an equilibrium problem for 2D elastic body with two semirigid inclusions. It is assumed that inclusions have a joint point, and we investigate a junction problem for these inclusions. The existence of solutions is proved, and different equivalent formulations of the problem are proposed. We investigate a convergence to infinity of a rigidity parameter of the semirigid inclusion. It is proved that in the limit, we obtain an equilibrium problem for the elastic body with a rigid inclusion and a semirigid one. A parameter identification problem is investigated. In particular, the existence of a solution to a suitable optimal control problem is proved. 相似文献
2.
V. I. Fedorov S. S. Popova A. N. Pisarchik 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(8):1235-1254
We have presented an overview of the literature and of our experimental data on the influence of electromagnetic radiation in the submillimeter spectral region on biological objects of molecular, cellular, and organism levels. Possible physical mechanisms involved and the reasons for limited development of the research in this spectral range are discussed. 相似文献
3.
O. Yu. Alekseev V. S. Borisov M. V. Davidovich N. F. Popova 《Journal of Communications Technology and Electronics》2006,51(11):1240-1247
Direct and inverse problems are considered for diffraction by an open end of a rectangular waveguide (RW) with a flange that adjoins a piecewise inhomogeneous planar layered lossy medium. Also considered are similar diffraction problems for a junction of an RW and a rectangular resonator filled with a multilayer medium and a junction of two RWs, one of which contains a multilayer plate. Such open and shielded waveguide probe structures (WPSs) are used for determination and nondestructive testing of parameters of multilayer samples. The direct problem is formulated on the basis of admittance and impedance algorithms with consideration for losses existing in the medium, flange, and screens. In this case, the approximation of the given aperture field allows obtainment of explicit solutions for open and shielded WPSs in the form of integrals. Solution of the inverse problem that lies in determining thicknesses, permittivities, and permeabilities of the layers from measured values of the magnitude of the reflection coefficient is obtained by minimizing the corresponding least-squares error and by constructing artificial neural networks. In order to increase the accuracy, it is proposed to use a two-port of errors and perform measurements for several positions of the sample with respect to the flange and different impedance conditions behind the sample. 相似文献
4.
N. A. Sivov A. I. Martynenko G. N. Bondarenko M. P. Filatova E. Yu. Kabanova N. I. Popova A. N. Sivov E. B. Kruts’ko 《Petroleum Chemistry》2006,46(1):41-59
Structures and compositions of the monomers guanidine acrylate and guanidine methacrylate, their homopolymers, and copolymers with diallyldimethylammonium chloride enriched in acrylate comonomer units were determined. It was shown that ampholytic copolymers, owing to their ionic nature, contained comonomeric guanidine acrylate or methacrylate units and diallyldimethylammonium chloride units, as well as the acrylate comonomer with the diallyl counterion and polymeric acrylate and diallyl ion pairs. It follows from IR and 1H NMR data that guanidine methacrylate has the same structure (with two hydrogen bonds) in the solid state and in solutions. Guanidine acrylate structures in the solid state and in dimethylsulfoxide are identical and analogous to guanidine methacrylate structure in this solvent. In water, the guanidine acrylate structure has another type of hydrogen bonding (with one hydrogen bond, where the proton is shifted toward the guanidine group). These features of hydrogen bonding of guanidine acrylate and guanidine methacrylate are also retained in their homopolymers and copolymers with diallyldimethylammonium chloride. It was shown that the thermal stability of the copolymers was higher than that of their homopolymers, confirming the formation of intramolecular ion pairs of oppositely charged units of ampholytic copolymers. Moreover, the thermal stability of guanidine methacrylate-diallyldimethylammonium chloride copolymers is higher than that of guanidine acrylate-diallyldimethylammonium chloride copolymers. 相似文献
5.
6.
YV Panchin YI Arshavsky TG Deliagina GN Orlovsky LB Popova AI Selverston 《Canadian Metallurgical Quarterly》1996,109(2):361-365
The locomotor activity in the marine mollusc Clione limacina has been found to be strongly excited by serotonergic mechanisms. In the present study putative serotonergic cerebropedal neurons were recorded simultaneously with pedal locomotor motoneurons and interneurons. Stimulation of serotonergic neurons produced acceleration of the locomotor rhythm and strengthening of motoneuron discharges. These effects were accompanied by depolarization of motoneurons, while depolarization of the generator interneurons was considerably lower (if it occurred at all). Effects of serotonin application on isolated locomotor and non-locomotor pedal neurons were studied. Serotonin (5 x 10(-7) to 1 x 10(-6) M) affected most pedal neurons. All locomotor neurons were excited by serotonin. This suggests that serotonergic command neurons exert direct influence on locomotor neurons. Effects of serotonin on nonlocomotor neurons were diverse, most neurons being inhibited by serotonin. Some effects of serotonin on locomotor neurons could not be reproduced by neuron depolarization. This suggests that, along with depolarization, serotonin modulates voltage-sensitive membrane properties of the neurons. As a result, serotonin promotes the endogenous rhythmical activity in neurons of the C. limacina locomotor central pattern generator. 相似文献
7.
R. G. Grebenshchikov V. F. Popova A. K. Shirvinskaya 《Glass Physics and Chemistry》2003,29(5):479-483
The phase equilibria in the LnAlO3–CaTiO3 (Ln = Dy, Y, Lu) systems are investigated and their phase diagrams are constructed for the first time. The thermal stability of the prepared solid solutions with a perovskite structure is studied. 相似文献
8.
9.
V. Z. Kutsova N. V. Popova A. G. Krimmel T. P. Chaikovskaya 《Metal Science and Heat Treatment》1992,34(11):704-707
Dnepropetrovsk Metallurgical Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 31–33, November, 1992. 相似文献
10.
K Ivanov M Popova P Denev C Kratchanov 《Zeitschrift für Lebensmittel-Untersuchung und -Forschung》1992,195(5):455-458
Laboratory experiments have been carried out for the removal of heavy metals from hydrogenated vegetable oils using hydrated polyuronides (degree of swelling from 4 to 12.8 ml/g) such as alginic acid, pectic and pectinic acids. The effect of the type of polyuronide, degree of esterification and oil treatment on the degree of demetalization has been studied. It has been shown that with increase in the degree of esterification of the polyuronide the efficiency of demetalization decreases. The second and third treatment of the hydrogenated oil with pectinic acid resulted in a high degree of heavy metal removal. The possibility of efficient demetalization of hydrogenated oils by treatment with water solutions of pectinic acids has also been demonstrated. The degree of metal ion removal increases with decreasing concentration of pectinic acids in the water solution. 相似文献