全文获取类型
收费全文 | 234篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 20篇 |
金属工艺 | 7篇 |
机械仪表 | 10篇 |
建筑科学 | 3篇 |
能源动力 | 4篇 |
轻工业 | 10篇 |
无线电 | 72篇 |
一般工业技术 | 41篇 |
冶金工业 | 28篇 |
原子能技术 | 13篇 |
自动化技术 | 24篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 11篇 |
2012年 | 5篇 |
2011年 | 12篇 |
2010年 | 9篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 12篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 15篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有236条查询结果,搜索用时 15 毫秒
101.
R. Senthilkumar S. Vaidyanathan B. Sivaraman 《Journal of Mechanical Science and Technology》2011,25(4):923-929
The orientation of the heat pipe plays the significant role in its performance. In specific orientations, the performance
of the heat pipe is directly related to the wick structure. In conventional heat pipe, the working fluid is used a negative
surface-tension gradient with temperature. It is an unfavorable one and it decreases the heat transport between the evaporator
section and the condenser section. An Aqueous solution of n-Pentanol having a positive surface tension gradient with temperature
is suggested as a working medium for heat pipe to improve the performance of capillary limit and operating stability. The
objective of this paper is to perform a comparative study of heat pipe performance using the aqueous solution of n-Pentanol
with water at various inclinations. The results are presented to demonstrate the merits and suitability of the aqueous solution
of n-Pentanol as a working fluid for heat pipe. 相似文献
102.
103.
Kunal Mishra Krishna P. Bastola Raman P. Singh Ranji Vaidyanathan 《Polymer Engineering and Science》2019,59(6):1199-1208
Graphene oxide (GO) nanoparticles were introduced in the interlaminar region of carbon fiber–epoxy composites by dispersing it in a thermoplastic polymer carrier such as polyvinylpyrrolidone (PVP). Mode‐I fracture toughness (GIC) was investigated using double cantilever beam testing to evaluate the effect of the GO on the delamination behavior of the composite. The GO content was varied from 0% to 7% by weight as a function of the PVP content. Improvement of ~100% in the Mode I fracture toughness (GIC) was observed compared to composites with no GO. The optimum amount of nanoparticles for improving the interlaminar fracture toughness was found to be ~0.007% by weight of the composite. The increase in the value of flexural strength value was also observed. Scanning electron microscopy of fracture surfaces, X‐ray diffraction, and transmission electron microscopy, and reflectance Fourier transform infrared spectra, as well as Raman spectroscopy results, are presented to support the conclusions. POLYM. ENG. SCI., 59:1199–1208 2019. © 2019 Society of Plastics Engineers 相似文献
104.
Hicks Brian M.; Vaidyanathan Uma; Patrick Christopher J. 《Canadian Metallurgical Quarterly》2010,1(1):38
Recent empirical investigations utilizing male prisoners have begun to validate clinical conceptualizations of primary and secondary psychopathy subtypes. We extended this literature by identifying similar psychopathic subtypes in female prisoners on the basis of personality structure using model-based cluster analysis. Secondary psychopaths (n = 39) were characterized by personality traits of negative emotionality and low behavioral constraint, an early onset of antisocial and criminal behavior, greater substance use and abuse, more violent behavior and institutional misconduct, and more mental health problems, including symptoms of posttraumatic stress disorder and suicide attempts. Primary psychopaths (n = 31) exhibited few distinguishing personality features but were prolific criminals especially in regards to nonviolent crime, and exhibited relatively few mental health problems despite substantial exposure to traumatic events. The results support alternative etiological pathways to antisocial and criminal behavior that are evident in personality structure as well as gender similarities and differences in the manifestation of psychopathic personalities. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
105.
G. Rajan S. K. Mitra P. P. Vaidyanathan Y. Neuvo 《Circuits, Systems, and Signal Processing》1990,9(1):99-121
In this paper we present a computationally efficient realization of single rate uniform FIR filter banks for audio and spectral analysis applications. The channel filters in the analysis bank are represented as modulated versions of a prototype narrowband lowpass FIR filter. Using the IFIR filter design technique [23], [24], this prototype lowpass filter can be designed very efficiently as a cascade of two subfilters. The IFIR filter design is extended for the two-branch realization of uniform filter banks with overlapping channels. A generalized structure is presented which can be used for bothodd andeven stacking arrangements of the channels. The shaping filter structures for the two branches are realized from a single delay line and a single set of filter coefficients, thus conserving the total number of multipliers and delays in the overall realization. The postfilter structure, in conjunction with the Generalized DFT matrices, performs the channel selection. The Generalized DFT matrices are used to provide the necessary modulation for the postfilter coefficients so that the appropriate passbands are selected for each channel of the analysis bank. This leads to a polyphase network realization of the postfilter structure. We derive conditions so that the original input signal can be exactly reconstructed from the channel signals.This work was supported in part by the National Science Foundation under Grant MIP 85-08017 and in part by a University of California MICRO Grant with matching support from the Rockwell Corporation and the Intel Corporation. 相似文献
106.
Prabhamani R. Patil G. Vaidyanathan 《International Journal of Engineering Science》1981,19(3):421-426
The effect of variable viscosity on the setting up of convection currents in a quiescent layer of a single component Boussinesq fluid saturating a porous medium bounded by two free boundaries has been analysed using a nonlinear technique. It is found that due to variable viscosity convection currents set in earlier. Both the Darcy and Brinkmann models have been used. 相似文献
107.
A self-contained discussion of discrete-time lossless systems and their properties and relevance in digital signal processing is presented. The basic concept of losslessness is introduced, and several algebraic properties of lossless systems are studied. An understanding of these properties is crucial in order to exploit the rich usefulness of lossless systems in digital signal processing. Since lossless systems typically have many input and output terminals, a brief review of multiinput multioutput systems is included. The most general form of a rational lossless transfer matrix is presented along with synthesis procedures for the FIR (finite impulse response) case. Some applications of lossless systems in signal processing are presented 相似文献
108.
The concept of biorthogonal partners has been introduced recently by the authors. The work presented here is an extension of some of these results to the case where the upsampling and downsampling ratios are not integers but rational numbers, hence, the name fractional biorthogonal partners. The conditions for the existence of stable and of finite impulse response (FIR) fractional biorthogonal partners are derived. It is also shown that the FIR solutions (when they exist) are not unique. This property is further explored in one of the applications of fractional biorthogonal partners, namely, the fractionally spaced equalization in digital communications. The goal is to construct zero-forcing equalizers (ZFEs) that also combat the channel noise. The performance of these equalizers is assessed through computer simulations. Another application considered is the all-FIR interpolation technique with the minimum amount of oversampling required in the input signal. We also consider the extension of the least squares approximation problem to the setting of fractional biorthogonal partners. 相似文献
109.
110.
The relative roles of avalanche multiplication and multiphoton absorption in laser-induced damage of dielectrics 总被引:4,自引:0,他引:4
The optical electric field strengths associated with pulsed laser exposures needed to produce conduction electron densities of 1018/cm3in several direct-gap alkali halides are calculated using three different models: a simplified avalanche model, the Keldysh formulation of multiphoton ionization, and a combination of the two. Numerical calculations are performed for crystalline NaCl, KCl, KBr, NaF, LiF, and CaF2 at wavelengths of 1.064, 0.694, 0.532, and 0.355 μm, for nanosecond and picosecond pulse durations. The results are compared with available experimental data resulting in the following observations: the damage field strengths predicted by the avalanche model scatter around the experimentally measured values, but they always agree within a factor of approximately four. The electric field strengths required for breakdown solely from the simultaneous absorption of four or more photons are significantly larger than the experimental values or the predictions of the avalanche model. However, in NaCl, KCl, and KBr the electric fields necessary for damage due to four-photon absorption are slightly smaller than those needed for catastrophic avalanche multiplication, and are in significantly closer agreement with the experimentally measured damage thresholds. When the avalanche and multiphoton models are combined in a direct manner the resulting thresholds are close to the smaller of the two previously calculated thresholds, and are in reasonable agreement with the experimental data with respect to their dependence on laser frequency and pulse duration. 相似文献