全文获取类型
收费全文 | 297篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 23篇 |
化学工业 | 42篇 |
金属工艺 | 3篇 |
机械仪表 | 14篇 |
建筑科学 | 2篇 |
能源动力 | 8篇 |
轻工业 | 13篇 |
水利工程 | 1篇 |
无线电 | 77篇 |
一般工业技术 | 41篇 |
冶金工业 | 45篇 |
原子能技术 | 1篇 |
自动化技术 | 34篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 11篇 |
2012年 | 20篇 |
2011年 | 13篇 |
2010年 | 9篇 |
2009年 | 8篇 |
2008年 | 10篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 10篇 |
2004年 | 5篇 |
2003年 | 8篇 |
2002年 | 11篇 |
2001年 | 12篇 |
2000年 | 9篇 |
1999年 | 10篇 |
1998年 | 18篇 |
1997年 | 13篇 |
1996年 | 5篇 |
1995年 | 12篇 |
1994年 | 7篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有304条查询结果,搜索用时 109 毫秒
1.
2.
W. Tang H.Z. Shi G. Xu B.S. Ong Z.D. Popovic J.C. Deng J. Zhao G.H. Rao 《Advanced materials (Deerfield Beach, Fla.)》2005,17(19):2307-2311
3.
Ph. A. Passeraub G. Rey-Mennet P. A. Besse H. Lorenz R. S. Popovic 《Sensors and actuators. A, Physical》1997,60(1-3):122-126
A high-sensitivity flat-coil inductive proximity sensor microsystem has been realized and successfully tested. The flat coil, made with CMOS-compatible post processes, is connected to a versatile differential relaxation oscillator electronic interface. In this new and simple interface, the excitation, the signal extraction and amplification are assured by only one operational amplifier. Experimental results on the microsystem confirm that large output frequency variations occur when a metallic target approaches the sensor. 相似文献
4.
Kostov A. Andrews B.J. Popovic D.B. Stein R.B. Armstrong W.W. 《IEEE transactions on bio-medical engineering》1995,42(6):541-551
Two machine learning techniques were evaluated for automatic design of a rule-based control of functional electrical stimulation (FES) for locomotion of spinal cord injured humans. The task was to learn the invariant characteristics of the relationship between sensory information and the FES-control signal by using off-line supervised training. Sensory signals were recorded using pressure sensors installed in the insoles of a subject's shoes and goniometers attached across the joints of the affected leg. The FES-control consisted of pulses corresponding to time intervals when the subject pressed on the manual push-button to deliver the stimulation during FES-assisted ambulation. The machine learning techniques used were the adaptive logic network (ALN) and the inductive learning algorithm (IL). Results to date suggest that, given the same training data, the IL learned faster than the ALN while both performed the test rapidly. The generalization was estimated by measuring the test errors and it was better with an ALN, especially if past points were used to reflect the time dimension. Both techniques were able to predict future stimulation events. An advantage of the ALN over the IL was that ALN's can be retrained with new data without losing previously collected knowledge. The advantages of the IL over the ALN were that the IL produces small, explicit, comprehensible trees and that the relative importance of each sensory contribution can be quantified 相似文献
5.
Weikle R.M. II Kim M. Hacker J.B. De Lisio M.P. Popovic Z.B. Rutledge D.B. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1992,80(11):1800-1809
Although quasi-optical techniques are applicable to a large variety of solid-state devices, special attention is given to transistors, which are attractive because they can be used as either amplifiers or oscillators. Experimental results for MESFET bar-grid and planar grid oscillators are presented. A MESFET grid amplifier that receives only vertically polarized waves at the input and radiates horizontally polarized waves at the output is discussed. These planar grids can be scaled for operation at millimeter- and submillimeter-wave frequencies. By using modern IC fabrication technology, planar grid oscillators and amplifiers containing thousands of devices can be built, thereby realizing an efficient means for large-scale power combining 相似文献
6.
Popovic M. Wada K. Akiyama S. Haus H.A. Michel J. 《Lightwave Technology, Journal of》2002,20(9):1762-1772
Air trench structures for reduced-size bends in low-index contrast waveguides are proposed. To minimize junction loss, the structures are designed to provide adiabatic mode shaping between low- and high-index contrast regions, which is achieved by the introduction of "cladding tapers." Drastic reduction in effective bend radius is predicted. We present two-dimensional (2-D) finite-difference time-domain/effective index method simulations of bends in representative silica index contrasts. We also argue that substrate loss, while present, can be controlled with such air trenches and reduced to arbitrarily low levels limited only by fabrication capabilities. The required trench depth, given an acceptable substrate loss, is calculated in three dimensions using an approximate equivalent current sheet method and also by a numerical solver for full-vector leaky modes. A simple, compact waveguide T-splitter using air trench bends is presented. 相似文献
7.
Duanka Vasovi Djordje Stojakovi Slavica Stankovi 《Journal of the American Ceramic Society》1987,70(1):23-C-
The use of BPO4 in the synthesis of crystalline AlPO4 has been investigated. The best results are obtained if BPO4 and hydrated alumina are heated in molten KCl: at 1050°C the conversion degree of BPO4 into AlPO4 is >90% (in 4 h). The product consists of the tridymite AlPO4 form. 相似文献
8.
Budimir Popovic 《Nutrient Cycling in Agroecosystems》1985,6(2):139-147
The effect of fertilization with urea and ammonium nitrate on nitrogen mineralization was studied in a series of laboratory incubation experiments. The samples (humus layer) were collected from field experiments with different applications of fertilizers during a period of 11–14 years. The nitrogen fertilization influenced some chemical properties of the humus layer such as pH, N-Kjeldahl content and the content of inorganic nitrogen, especially in the samples from North Sweden. Nitrate nitrogen was formed in humus samples classified as non-nitrifying in several cases, usually after urea fertilization. 相似文献
9.
Room temperature formability testing was performed on an AlMg6.8 type alloy sheet with a fully recrystallized structure (average grain diameter 18 m) and after partial annealing with a retained deformed structure. The yield strengths attained after full recrystallization and after partial annealing, were 175 and 283 MPa respectively. Such an increase in strength is followed by formability degradation, maximized around the plain strain state to either 42%, as obtained using the limiting dome height test (LDH), or 35% after using forming limit curves (FLC). A comparison with known high-strength formable alloys has shown that the tested alloy in the recrystallized condition has a better stretch formability (at the same or even higher yield stress level), while in the unrecrystallized-partially annealed condition it has a lower formability, limiting its application to moderate forming requirements for very high-strength parts. © 1998 Chapman & Hall 相似文献
10.
CAD based shape optimization for gas turbine component design 总被引:1,自引:0,他引:1
Djordje Brujic Mihailo Ristic Massimiliano Mattone Paolo Maggiore Gian Paolo De Poli 《Structural and Multidisciplinary Optimization》2010,41(4):647-659
In order to improve product characteristics, engineering design makes increasing use of Robust Design and Multidisciplinary
Design Optimisation. Common to both methodologies is the need to vary the object’s shape and to assess the resulting change
in performance, both executed within an automatic loop. This shape change can be realised by modifying the parameter values
of a suitably parameterised Computer Aided Design (CAD) model. This paper presents the adopted methodology and the achieved
results when performing optimisation of a gas turbine disk. Our approach to hierarchical modelling employing design tables
is presented, with methods to ensure satisfactory geometry variation by commercial CAD systems. The conducted studies included
stochastic and probabilistic design optimisation. To solve the multi-objective optimisation problem, a Pareto optimum criterion
was used. The results demonstrate that CAD centric approach enables significant progress towards automating the entire process
while achieving a higher quality product with the reduced susceptibility to manufacturing imperfections. 相似文献