全文获取类型
收费全文 | 2338篇 |
免费 | 39篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 157篇 |
综合类 | 3篇 |
化学工业 | 517篇 |
金属工艺 | 51篇 |
机械仪表 | 51篇 |
建筑科学 | 37篇 |
矿业工程 | 1篇 |
能源动力 | 97篇 |
轻工业 | 138篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 228篇 |
一般工业技术 | 477篇 |
冶金工业 | 379篇 |
原子能技术 | 47篇 |
自动化技术 | 195篇 |
出版年
2023年 | 5篇 |
2022年 | 30篇 |
2021年 | 43篇 |
2020年 | 14篇 |
2019年 | 15篇 |
2018年 | 18篇 |
2017年 | 23篇 |
2016年 | 37篇 |
2015年 | 26篇 |
2014年 | 50篇 |
2013年 | 91篇 |
2012年 | 74篇 |
2011年 | 124篇 |
2010年 | 75篇 |
2009年 | 91篇 |
2008年 | 112篇 |
2007年 | 114篇 |
2006年 | 91篇 |
2005年 | 74篇 |
2004年 | 70篇 |
2003年 | 72篇 |
2002年 | 66篇 |
2001年 | 53篇 |
2000年 | 44篇 |
1999年 | 67篇 |
1998年 | 149篇 |
1997年 | 105篇 |
1996年 | 60篇 |
1995年 | 57篇 |
1994年 | 43篇 |
1993年 | 47篇 |
1992年 | 28篇 |
1991年 | 44篇 |
1990年 | 32篇 |
1989年 | 26篇 |
1988年 | 43篇 |
1987年 | 24篇 |
1986年 | 25篇 |
1985年 | 30篇 |
1984年 | 27篇 |
1983年 | 17篇 |
1982年 | 15篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1979年 | 22篇 |
1978年 | 19篇 |
1977年 | 9篇 |
1976年 | 20篇 |
1975年 | 5篇 |
1973年 | 5篇 |
排序方式: 共有2385条查询结果,搜索用时 15 毫秒
1.
Atsuki Yamaguchi Kazuki Fukui Yuki Fujiwara Shingo Tamaki Sachie Kusaka Fuminobu Sato 《Journal of Nuclear Science and Technology》2021,58(1):80-86
ABSTRACT It is important to perform neutron transport simulations with accurate nuclear data in the neutronics design of a fusion reactor. However, absolute values of large-angle scattering cross sections vary among nuclear data libraries even for well-examined nuclide of iron. Benchmark experiments focusing on large-angle scattering cross sections were thus performed to confirm the correctness of nuclear data libraries. The series benchmark experiments were performed at a DT neutron source facility, OKTAVIAN of Osaka University, Japan, by the unique experimental system established by the authors’ group, which can extract only the contribution of large-angle scattering reactions. This system consists of two shadow bars, target plate (iron), and neutron detector (niobium). Two types of shadow bars were used and four irradiations were conducted for one experiment, so that contribution of room-return neutrons was effectively removed and only large-angle scattering neutrons were extracted from the measured four Nb reaction rates. The obtained experimental results were compared with calculations for five nuclear data libraries including JENDL-4.0, JEFF.-3.3, FENDL-3.1, ENDF/B- VII, and recently released ENDF/B-VIII. It was found from the comparison that ENDF/B-VIII showed the best result, though ENDF/B-VII showed overestimation and others are in large underestimation at 14 MeV. 相似文献
2.
In a plant consisting of parallelized microreactors (MRs), the product quality is lowered because of a lack of flow uniformity among them when blockage occurs. It is not practical to install sensors in every MR from the viewpoint of cost when detecting the blocked MRs. In the previous study, the multiple blockage detection (MBD) method using a small number of sensors was proposed, but its performance became low when the number of sensors decreased. Here, the conventional algorithm for MBD is improved by considering the process behavior on blockage occurrence, and the effectiveness of the improved algorithm is demonstrated through a numerical case study. The effects of flow distributor types and sensor types on the MBD performance are numerically investigated. 相似文献
3.
Shohei Minagawa Shoji Fujiwara Takeshi Hashimoto Takashi Hayashita 《International journal of molecular sciences》2021,22(9)
Cyclodextrins (CyDs) are water-soluble host molecules possessing a nanosized hydrophobic cavity. In the realm of molecular recognition, this cavity is used not only as a recognition site but also as a reaction medium, where a hydrophobic sensor recognizes a guest molecule. Based on the latter concept, we have designed a novel supramolecular sensing system composed of Zn(II)-dipicolylamine metal complex-based azobenzene (1-Zn) and 3A-amino-3A-deoxy-(2AS,3AS)-γ-cyclodextrin (3-NH2-γ-CyD) for sensing adenosine-5′-triphosphate (ATP). 1-Zn showed redshifts in the UV-Vis spectra and induced circular dichroism (ICD) only when both ATP and 3-NH2-γ-CyD were present. Calculations of equilibrium constants indicated that the amino group of 3-NH2-γ-CyD was involved in the formation of supramolecular 1-Zn/3-NH2-γ-CyD/ATP. The Job plot of the ICD spectral response revealed that the stoichiometry of 1-Zn/3-NH2-γ-CyD/ATP was 2:1:1. The pH effect was examined and 1-Zn/3-NH2-γ-CyD/ATP was most stable in the neutral condition. The NOESY spectrum suggested the localization of 1-Zn in the 3-NH2-γ-CyD cavity. Based on the obtained results, the metal coordination interaction of 1-Zn and the electrostatic interaction of 3-NH2-γ-CyD were found to take place for ATP recognition. The “reaction medium approach” enabled us to develop a supramolecular sensing system that undergoes multi-point interactions in water. This study is the first step in the design of a selective sensing system based on a good understanding of supramolecular structures. 相似文献
4.
5.
Ohsaki Makoto Fujiwara Jun Takeda Fumiyoshi 《International Journal of Mechanics and Materials in Design》2020,16(4):883-896
International Journal of Mechanics and Materials in Design - A simple iterative method is presented for cutting pattern optimization of frame-supported and pneumatic membrane structures for... 相似文献
6.
On an earthspace propagation path with the low elevation angle of 10 deg, the phase between co- and crosspolar signals occasionally showed rapid and irregular fluctuations during fine weather. These fluctuations were generally significant during the daytime, and were strongly in phase with the occurrence of the copolar amplitude scintillations. This could be attributed to the combined effects of the crosspolar phase pattern of the receiving antenna and small fluctuations of the angle of arrival of the radiowaves. 相似文献
7.
Yuansheng Tang Fujiwara T. Kasami T. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2002,48(8):2401-2405
The generalized minimum distance (GMD) and Chase (1972) decoding algorithms are some of the most important suboptimum bounded distance decoding algorithms for binary linear block codes over an additive white Gaussian noise (AWGN) channel. We compute the limitation of the ratio between the probability of decoding error for the GMD or any one of the Chase decoding algorithms and that of the maximum-likelihood (ML) decoding when the signal-to-noise ratio (SNR) approaches infinity. If the minimum Hamming distance of the code is greater than 2, the limitation is shown to be equal to 1 and thus the GMD and Chase decoding algorithms are asymptotically optimum. 相似文献
8.
This paper introduces a new concept of testability called consecutive testability and proposes a design-for-testability method for making a given SoC consecutively testable based on integer linear programming problem. For a consecutively testable SoC, testing can be performed as follows. Test patterns of a core are propagated to the core inputs from test pattern sources (implemented either off-chip or on-chip) consecutively at the speed of system clock. Similarly the test responses are propagated to test response sinks (implemented either off-chip or on-chip) from the core outputs consecutively at the speed of system clock. The propagation of test patterns and responses is achieved by using interconnects and consecutive transparency properties of surrounding cores. All interconnects can be tested in a similar fashion. Therefore, it is possible to test not only logic faults but also timing faults that require consecutive application of test patterns at the speed of system clock since the consecutively testable SoC can achieve consecutive application of any test sequence at the speed of system clock. 相似文献
9.
Kitakami O. Ogawa Y. Fujiwara H. Kugiya F. Suzuki M. 《IEEE transactions on magnetics》1989,25(3):2607-2611
A Co-Cr film deposited directly on a substrate has an initial growth layer with low coercivity. However, the existence of a Ti underlayer prevents the formation of such a layer. As a result, Co-Cr film deposited on a Ti underlayer has high perpendicular anisotropy and coercivity even in cases of extremely thin film thickness (200 Å). As for the read-write characteristics of Co-Cr thin-film media, the existence of such an initial growth layer greatly improves the reproduced output level. The cause for this is considered to be that the free charges which appear on the back surface of the perpendicular recording layer are reduced and the demagnetization field acting on the recorded magnetization subsequently decreases due to the existence of the initial growth layer 相似文献
10.