全文获取类型
收费全文 | 1063篇 |
免费 | 56篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 19篇 |
化学工业 | 263篇 |
金属工艺 | 41篇 |
机械仪表 | 20篇 |
建筑科学 | 20篇 |
能源动力 | 49篇 |
轻工业 | 124篇 |
水利工程 | 4篇 |
石油天然气 | 3篇 |
无线电 | 187篇 |
一般工业技术 | 172篇 |
冶金工业 | 95篇 |
原子能技术 | 8篇 |
自动化技术 | 118篇 |
出版年
2024年 | 3篇 |
2023年 | 12篇 |
2022年 | 22篇 |
2021年 | 37篇 |
2020年 | 23篇 |
2019年 | 27篇 |
2018年 | 39篇 |
2017年 | 32篇 |
2016年 | 37篇 |
2015年 | 22篇 |
2014年 | 50篇 |
2013年 | 66篇 |
2012年 | 43篇 |
2011年 | 62篇 |
2010年 | 53篇 |
2009年 | 53篇 |
2008年 | 44篇 |
2007年 | 40篇 |
2006年 | 28篇 |
2005年 | 24篇 |
2004年 | 18篇 |
2003年 | 20篇 |
2002年 | 16篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 18篇 |
1998年 | 33篇 |
1997年 | 26篇 |
1996年 | 25篇 |
1995年 | 18篇 |
1994年 | 17篇 |
1993年 | 15篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 19篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 12篇 |
1979年 | 8篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有1123条查询结果,搜索用时 15 毫秒
1.
Youngseok Lee Cheolmin Park Nagarajan Balaji Youn-Jung Lee Vinh Ai Dao 《Israel journal of chemistry》2015,55(10):1050-1063
Over the past few decades, crystalline silicon solar cells have been extensively studied due to their high efficiency, high reliability, and low cost. In addition, these types of cells lead the industry and account for more than half of the market. For the foreseeable future, Si will still be a critical material for photovoltaic devices in the solar cell industry. In this paper, we discuss key issues, cell concepts, and the status of recent high-efficiency crystalline silicon solar cells. 相似文献
2.
A model to describe the effect of unequal reactivity on curing of a diisocyanate with water, polyol and a diol was developed. The model predicts whether a given initial composition would gel or not and the fractional conversions of functional groups at the gel point. It has been shown that the relative speeds of reaction of water and hydroxyl groups can be used to classify water's behaviour as that of a (i) nonreactive diluent (ii) monofunctional blocking agent and (iii) chain extender capable of connecting branch points. 相似文献
3.
Sankaralingam K. Nagarajan R. Haiming Liu Changkyu Kim Jaehyuk Huh Burger D. Keckler S.W. Moore C. 《Micro, IEEE》2003,23(6):46-51
The Tera-op reliable intelligently adaptive processing system (TRIPS) architecture seeks to deliver system-level configurability to applications and runtime systems. It does so by employing the concept of polymorphism, which permits the runtime system to configure the hardware execution resources to match the mode of execution and demands of the compiler and application. 相似文献
4.
5.
Giboney K.S. Nagarajan R.L. Reynolds T.E. Allen S.T. Mirin R.P. Rodwell M.J.W. Bowers J.E. 《Photonics Technology Letters, IEEE》1995,7(4):412-414
Results of the first fabrication and measurement of travelling-wave photodetectors are reported. The devices have bandwidths as high as 172 GHz, the highest reported for a p-i-n photodetector, and bandwidth-efficiency products as large as 76 GHz, the largest reported for any photodetector without gain. Comparisons with vertically illuminated and waveguide photodetectors fabricated on the same wafer establish the superior performance of travelling-wave photodetectors. Microwave loss on the travelling-wave photodetector structure is identified as a bandwidth limitation 相似文献
6.
7.
The UvrA and UvrB proteins form part of the UvrABc endonuclease, which is responsible for nucleotide excision repair in Escherichia coli. Using a mobility shift gel assay we have studied the binding of UvrA dimer, UvrB monomer and UvA(2)B trimer complexes with 40, 50 and 136 bp (32)P-end-labelled DNA fragments adducted with aflatoxin B(1). UvrA was shown to re-associate with adduct specific UvrB: DNA complexes, a phenomenon which could be reversed by the addition of 500 mM potassium chloride or anti-UvrA anti-sera. Re-association was shown to be UvrA concentration dependent. Re-association of UvrA(2)B to the UvrB:DNA complex was not seen. We have also shown that the UvrB:DNA complex, in the case of aflatoxin B(1), is extremely stable with a half-life excess of 400 min and that fragment termini are not a specific substrate for UvrA binding. 相似文献
8.
Neural networks for signal detection in non-Gaussian noise 总被引:1,自引:0,他引:1
We employ neural networks to detect known signals in additive non-Gaussian noise. Training of the neural network for signal detection and its operation at some specified probability of false alarm are discussed. Performance of neural detectors are presented under several non-Gaussian noise environments and are compared with those of matched filter and locally optimum detectors 相似文献
9.
Takamichi Iida Roderick Guthrie Nagendra Tripathi 《Metallurgical and Materials Transactions B》2006,37(4):559-564
By combining the modified Stokes-Einstein formula with the authors’ model for the melting-point viscosity, the authors present
a model for accurate predictions of self-diffusivity of liquid metallic elements. The model is expressed in terms of well-known
physical quantities and has been applied to various liquid metallic elements for which experimental data are available. The
results of calculations show that agreement with experimental data is excellent; the uncertainties in the calculations of
the self-diffusivities in various liquid metallic elements are equal to the uncertainties associated with experimental measurements.
Also, the authors propose an expression for the temperature dependence of self-diffusivity in liquid metallic elements in
terms of melting-point temperature. Using the model, self-diffusivity data are predicted for liquid iron, cobalt, nickel,
titanium, aluminum, magnesium, silicon, and so forth. 相似文献
10.
Numerical simulation of annular-phased arrays of dipoles forhyperthermia of deep-seated tumors 总被引:1,自引:0,他引:1
We have used the finite-difference time domain (FDTD) method to calculate the SAR distributions from an annular-phased array of eight dipole antennas coupled through water "boluses" in anatomically based three-dimensional models of the human body. We evaluated the effect of tapered bolus chambers, frequency (100-120 MHz), dipole length (17-30 cm), and phase and amplitude of power to the various dipoles on the ability to focus energy in the region of deep-seated tumors in the prostate and the liver. Assuming tumor conductivity and permittivity to be similar or slightly higher than surrounding normal tissues, calculations indicate that adjustment of the noted parameters should result in considerable improvement in focusing of SAR distributions in tumor-bearing regions. If such calculations can be shown to correctly predict empirical measurements from complex inhomogeneous (although not necessarily anatomically correct) phantoms, they may be useful for hyperthermia treatment planning based on patient-specific anatomic models. 相似文献