全文获取类型
收费全文 | 128篇 |
免费 | 6篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 17篇 |
机械仪表 | 2篇 |
建筑科学 | 3篇 |
轻工业 | 11篇 |
无线电 | 27篇 |
一般工业技术 | 26篇 |
冶金工业 | 16篇 |
原子能技术 | 1篇 |
自动化技术 | 29篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 12篇 |
2009年 | 3篇 |
2008年 | 11篇 |
2007年 | 11篇 |
2006年 | 8篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有134条查询结果,搜索用时 31 毫秒
11.
Zohar Yosibash Elad Priel Dominique Leguillon 《International Journal of Fracture》2006,141(1-2):291-312
The failure criterion of Leguillon at reentrant corners in brittle elastic materials (Leguillon 2002, Eur J Mech A/Solids
21: 61–72; Leguillon et al. (2003), Eur J Mech A—Solids 22(4): 509–524) validated in (Yosibash et al. 2004, Int J Fract 125(3–4):
307–333) for mode I loading is being extended to mixed mode loading and is being validated by experimental observations. We
present an explicit derivation of all quantities involved in the computation of the failure criterion. The failure criterion
is validated by predicting the critical load and crack initiation angle of specimens under mixed mode loading and comparison
to experimental observations on PMMA (polymer) and Macor (ceramic) V-notched specimens. 相似文献
12.
We propose the Gaussian content (GC) as an optional quality parameter for the characterization of laser beams. It is defined as the overlap integral of a given field with an optimally defined Gaussian. The definition is especially suited for applications where coherence properties are targeted. Mathematical definitions and basic calculation procedures are given along with results for basic beam profiles. The coherent combination of an array of laser beams and the optimal coupling between a diode laser and a single-mode fiber are elaborated as application examples. The measurement of the GC and its conservation upon propagation are experimentally confirmed. 相似文献
13.
14.
A mathematical model for large amplitude wave propagation in a thin walled distensible tube is developed. The tube wall is considered as a membranic shell made of an incompressible, non-linear viscoelastic material with cylindrical orthotropy. The fluid is regarded as incompressible and inviscid and the flow is quasi-one-dimensional. The case of a pressure step applied at one end of a uniform straight tube is solved as an example. The system of partial differential equations, describing the motions of the fluid and the wall, are integrated numerically by using a two-step explicit scheme. Flow and deformation variables as well as the wave velocity are determined in time and space. 相似文献
15.
16.
The capability to fabricate nanoscale structures is a fundamental step toward realizing the promise and potential of nanotechnology. We report on precise manipulation and thermal processing using 100-nm polystyrene latex nanoparticles. This approach is illustrated by fabricating a three-dimensional nanostructure by using an AFM tip to position nanoparticles and then thermally processing to "sinter" the particles to form a contiguous, stable structure. We suggest that this is a general approach, but the use of polystyrene latex particles offers an advantage of low-temperature processing. Use of polystyrene latex also extends the range of materials for which we have demonstrated manipulation and suggests applications including fluorescent doping and electrically conducting polymers. 相似文献
17.
Noam Ben-Eliezer Eddy Solomon Elad Harel Nava Nevo Lucio Frydman 《Magma (New York, N.Y.)》2012,25(6):433-442
Object
An approach has been recently introduced for acquiring arbitrary 2D NMR spectra or images in a single scan, based on the use of frequency-swept RF pulses for the sequential excitation and acquisition of the spins response. This spatiotemporal-encoding (SPEN) approach enables a unique, voxel-by-voxel refocusing of all frequency shifts in the sample, for all instants throughout the data acquisition. The present study investigates the use of this full-refocusing aspect of SPEN-based imaging in the multi-shot MRI of objects, subject to sizable field inhomogeneities that complicate conventional imaging approaches.Materials and methods
2D MRI experiments were performed at 7 T on phantoms and on mice in vivo, focusing on imaging in proximity to metallic objects. Fully refocused SPEN-based spin echo imaging sequences were implemented, using both Cartesian and back-projection trajectories, and compared with k-space encoded spin echo imaging schemes collected on identical samples under equal bandwidths and acquisition timing conditions.Results
In all cases assayed, the fully refocused spatiotemporally encoded experiments evidenced a ca. 50?% reduction in signal dephasing in the proximity of the metal, as compared to analogous results stemming from the k-space encoded spin echo counterparts.Conclusion
The results in this study suggest that SPEN-based acquisition schemes carry the potential to overcome strong field inhomogeneities, of the kind that currently preclude high-field, high-resolution tissue characterizations in the neighborhood of metallic implants. 相似文献18.
19.
Noncommensurate 2D interfaces hold great promise toward low friction and nanoelectromechanical applications. For identical constituents, the crystals interlock at specific rotational configurations leading to high barriers for slide. In contrast, nonidentical constituents comprising different lattice parameters should enable robust superlubricity for all rotational configurations. This is however not the case for gold–graphite interfaces, as both theory and experiments show scaling behavior of the sliding force as a function of the interface contact area. By simulating the sliding force for gold–graphite interfaces, this work shows that the origin for high force barriers at special angular configurations is a result of commensurability between the moiré structure and the contact geometry. Consequently, this paper suggests new geometries that can potentially overcome such commensurability effects to enable robust superlubricity. 相似文献
20.
Poly(vinyl chloride) (PVC) was plasticized with a given polyester. The resulting exudate under humid conditions was qualitatively analyzed by GPC and GLC. The exudate was found to have a greater concentration of low molecular weight species than the origional polyester. Further, a much higher hydroxyl group concentration was present. The described polyester was also fractionated and characterization studies were performed. The relative migratory aptitude in PVC of these moieties was studied under humied conditions. The fraction with the greatest concentration of low molecular weight species and the highest hydroxyl concentration was exuded first. 相似文献