全文获取类型
收费全文 | 561篇 |
免费 | 16篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 8篇 |
综合类 | 10篇 |
化学工业 | 69篇 |
金属工艺 | 27篇 |
机械仪表 | 8篇 |
建筑科学 | 9篇 |
矿业工程 | 17篇 |
能源动力 | 2篇 |
轻工业 | 31篇 |
水利工程 | 4篇 |
石油天然气 | 14篇 |
武器工业 | 1篇 |
无线电 | 24篇 |
一般工业技术 | 56篇 |
冶金工业 | 272篇 |
原子能技术 | 18篇 |
自动化技术 | 13篇 |
出版年
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 16篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 16篇 |
2014年 | 5篇 |
2013年 | 19篇 |
2012年 | 19篇 |
2011年 | 24篇 |
2010年 | 17篇 |
2009年 | 13篇 |
2008年 | 15篇 |
2007年 | 15篇 |
2006年 | 11篇 |
2005年 | 13篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 65篇 |
1997年 | 44篇 |
1996年 | 28篇 |
1995年 | 21篇 |
1994年 | 13篇 |
1993年 | 22篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 13篇 |
1976年 | 29篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1967年 | 5篇 |
排序方式: 共有583条查询结果,搜索用时 10 毫秒
21.
大气气溶胶是气候变化与遥感定量化等的重要影响因素,研究气溶胶光学特性具有重要意义.基于高分五号卫星搭载的大气气溶胶多角度偏振探测仪(Directional polarimetric camera,DPC)过境中国区域的数据,开展了气溶胶光学厚度的反演研究.基于矢量辐射传输模型6SV计算构建气溶胶光学特性查找表,采用Ro... 相似文献
22.
E. BERT
TI 《International journal for numerical methods in engineering》1996,39(15):2647-2671
A hierarchic sequence of equilibrium models in terms of stresses assumed to be not a priori symmetric is derived for cylindrical bending of laminated composites, using first-order stress functions. The stress field of each hierarchic model satisfies a priori (i) the translational equilibrium equations and the stress boundary conditions of two-dimensional elasticity, and (ii) the continuity requirement for the transverse shear and normal stresses at the lamina interfaces. The levels of hierarchy correspond to the degree to which the two first-order compatibility equations and the rotational equilibrium equation of two-dimensional elasticity are satisfied. The numerical solution is based on Fraeijs de Veubeke's dual mixed variational principle, employing the p-version of the finite element method. The number of degrees of freedom is independent of the number of the layers in the laminate. Results are obtained directly for the stresses and rotations; the displacement field is obtained in the post-processing phase by integration. Numerical results with comparisons show the capability of the mathematical and numerical models proposed. 相似文献
23.
水体下综放开采技术的研究 总被引:1,自引:0,他引:1
根据水体下开采的研究现状,在水体下适当地使用综合放顶煤开采工艺,确定合理的开采上限,可更好地提高效率,实现煤矿高产高效的目的.依据水体下开采的特殊性,确定安全开采的合理性. 相似文献
24.
AV Krylov YN Antonenko EA Kotova TI Rokitskaya AA Yaroslavov 《Canadian Metallurgical Quarterly》1998,440(1-2):235-238
Effect of a cationic polymer, poly(L-lysine), on the kinetic properties of ionic channels formed by neutral gramicidin A (gA) and its negatively charged analogue O-pyromellitylgramicidin (OPg) in a bilayer lipid membrane is studied using a method of sensitized photoinactivation. This newly developed method is based on the analysis of transmembrane current transients induced by a flash in the presence of a photosensitizer. It has been shown previously that the time course of the flash-induced current decrease in most cases follows a single exponential decay with an exponential factor (tau, the characteristic time of photoinactivation) that correlates well with the single-channel lifetime. Addition of polylysine does not affect tau for gA channels, but causes a substantial increase in tau for OPg channels. This effect is reversed by addition of polyacrylic acid. The deceleration of the photoinactivation kinetics is ascribed to electrostatic interaction of polylysine with OPg probably resulting in OPg clustering. The latter can stabilize the channel state by reducing the rotational and lateral mobility of OPg monomers and dimers, and thus increase the single channel lifetime. 相似文献
25.
26.
Nadezhda S. Tian Tamara K. Meleshko Galina A. Polotskaya Iosif V. Gofman Anna V. Kashina Nina V. Kukarkina Elena N. Vlasova Zoolsho F. Zoolshoev Alexander V. Yakimansky 《Polymer Engineering and Science》2020,60(3):481-490
Composite films based on polyamide (poly(m-phenylene-iso-phthalamide)) (PA) and a brush-like polymer with polyimide (PI) backbone and side poly(methyl methacrylate) chains (PI-PMMA) were prepared by mixing individual solutions of PA and PI-PMMA and subsequent film casting. Macromolecular brushes with the same backbone length and density of side chains but with various lengths of side PMMA chains were synthesized via activator generated by electron transfer atom transfer radical polymerization. Interactions between PA and PI-PMMA, as well as distribution of PI-PMMA filler inside the PA matrix, were studied by viscometry, dynamic light scattering, differential scanning calorimetry, scanning electron microscopy, and IR spectroscopy. The mechanical properties of polymer samples were also investigated. Microphase separation was revealed in PA/PI-PMMA films. The length of side chains influences interactions between PA and PI-PMMA. At the same time, the degree of reduction in the rigidity parameters and in the elasticity parameter depends on the side chain length. Diffusion membranes were prepared on the basis of compositions with the best mechanical properties; these membranes proved to be highly efficient in pervaporation of methanol–hexane mixture. It was established that the fluxes and separation factors of the studied membranes are several times higher as compared to the corresponding characteristics of known commercial membranes. POLYM. ENG. SCI., 60:481–490, 2020. © 2019 Society of Plastics Engineers 相似文献
27.
T. B. Ershova N. M. Vlasova M. A. Teslina I. A. Astapov 《Theoretical Foundations of Chemical Engineering》2016,50(5):846-850
The possibility to prepare metal ceramics based on carbides and titanium carbonitrides from intermetal alloy scrap has been studied. The influence of sintering conditions on phase and structure formation processes in a metal ceramics material and on the composition and properties of the prepared material has been analyzed. 相似文献
28.
T. V. Bocharova A. N. Vlasova G. O. Karapetyan V. G. Kuryavyi A. M. Mironov N. O. Tagil’tseva 《Glass Physics and Chemistry》2008,34(6):683-692
The induced optical absorption and EPR absorption spectra of fluorophosphate glasses of the compositions 40Ba(PO3)2 · 60MgCaSrBaAl2F14 and 5Ba(PO3)2 · 95MgCaSrBaAl2F14 doped with Tb3+ and Eu3+ ions are investigated within the model of the effective capture volume of free carriers. The concentration dependences of the relative number of radiation centers on the dopant concentration in fluorophosphate glasses are analyzed. It is established that the character of the distribution of dopant ions in glasses depends on the dopant concentration and the structure of the glass. The critical concentrations at which the oxygen local environment of Eu3+ or Tb3+ ions in the structure of fluorophosphate glasses transforms into a mixed local environment are determined for glasses of the compositions under investigation. 相似文献
29.
针对紧密对接微间隙焊缝,研究磁光成像识别的焊缝图像恢复算法,建立基于能量泛函的全变分(Total Variation)图像恢复模型,解决磁光图像退化和清晰度不高的问题.根据偏微分方程论证全变分图像恢复模型解的存在性,将图像恢复过程转化为约束最优化问题,通过泛函变分给出模型的欧拉-拉格朗日方程,对数值近似解的离散形式进行磁光图像恢复.试验分析采用全变分图像恢复模型降噪的同时,保持焊缝图像良好的边缘和纹理特征.结果表明,经全变分模型图像恢复后可有效提高焊缝磁光图像质量,准确地测量焊缝位置. 相似文献
30.
N. N. Vlasova E. N. Oborina L. I. Belousova L. I. Larina 《Protection of Metals and Physical Chemistry of Surfaces》2018,54(1):71-77
The synthesis of organosilicon derivative monomers and polymers characterized with sorption properties has been performed. The synthesized organosilicon polymers have been investigated as sorbents for heavy (Hg(II)) and noble (Ag(I), Au(III), Rh(II), Pd(II), and Pt(IV)) metals. The coefficients of the interphase metal distribution have been estimated. 相似文献