全文获取类型
收费全文 | 1242篇 |
免费 | 38篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 58篇 |
综合类 | 2篇 |
化学工业 | 336篇 |
金属工艺 | 30篇 |
机械仪表 | 26篇 |
建筑科学 | 18篇 |
能源动力 | 70篇 |
轻工业 | 119篇 |
石油天然气 | 3篇 |
无线电 | 120篇 |
一般工业技术 | 242篇 |
冶金工业 | 158篇 |
原子能技术 | 23篇 |
自动化技术 | 77篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 24篇 |
2020年 | 18篇 |
2019年 | 12篇 |
2018年 | 21篇 |
2017年 | 14篇 |
2016年 | 28篇 |
2015年 | 25篇 |
2014年 | 30篇 |
2013年 | 58篇 |
2012年 | 49篇 |
2011年 | 62篇 |
2010年 | 48篇 |
2009年 | 43篇 |
2008年 | 71篇 |
2007年 | 56篇 |
2006年 | 50篇 |
2005年 | 45篇 |
2004年 | 30篇 |
2003年 | 48篇 |
2002年 | 27篇 |
2001年 | 32篇 |
2000年 | 12篇 |
1999年 | 35篇 |
1998年 | 75篇 |
1997年 | 55篇 |
1996年 | 31篇 |
1995年 | 23篇 |
1994年 | 24篇 |
1993年 | 30篇 |
1992年 | 19篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 18篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 14篇 |
1982年 | 7篇 |
1981年 | 13篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1974年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有1282条查询结果,搜索用时 15 毫秒
121.
Akihiko Yamaguchi Kosuke Kurokawa Toru Uno Masaharu Takahashi 《Solar Energy Materials & Solar Cells》2003,75(3-4):679-686
In this paper, the authors investigated the reflection and absorption characteristics of a general photovoltaic (PV) module. As a result, the electromagnetic waves could be attenuated only 6 dB in typical PV module. However, if the PV module is installed in the outer wall of buildings, electromagnetic interference is caused by the surroundings. To reduce this electromagnetic interference, the authors suggested a method to absorb electromagnetic wave using multiple PV modules that have deference impedance, and simulation was performed. As a result, it was confirmed that using a typical PV module and the PV module including electronic device, the reflection waves of those PV modules could be attenuated up to 12 dB. 相似文献
122.
Tadatoshi Sugiura Takao Yamada Hiroyuki Nakamura Mariko Umeya Koichi Sakuta Kosuke Kurokawa 《Solar Energy Materials & Solar Cells》2003,75(3-4):767-779
This paper is about measurements, analyses and evaluation of residential PV systems in the Japanese Monitoring Program, on which JQA was subsidized by NEDO (New Energy Development and Industrial Technology Organization) that is currently proceeding [NSS R&D] from FY1997 to FY 2000.The aim of this investigation refers, through the data evaluation and analyses, to obtain knowledge required for optimizing design of PV systems, such as system performance, characteristics and regional dependency under practical operation and to develop the system evaluation technology on the design parameter method. 相似文献
123.
Shigeaki Abe Yoshinori Nagoya Fumio Watari Hiroto Tachikawa 《Computational Materials Science》2011,50(9):2640-2643
The evaporation processes of water molecules adsorbed in the edge region of graphene have been investigated by means of direct MO–MD method. A large system composed of 29 water molecules and a graphene sheet (C96H24) was used as a model system. The edge carbon atom of graphene was terminated by hydrogen atom. The geometry optimization showed that the water molecules interact with the hydrogen atoms in the edge region of graphene. At low temperature (300 K), the water molecules were dissociated as water clusters from the graphene. On the other hand, in addition to the dissociation of water clusters, the isolated water molecule was also found as dissociation product at high temperature (500 K). The mechanism of water evaporation was discussed on the basis of theoretical results. 相似文献
124.
A microcarrier is used for the three-dimensional (3D) culture of adhesion-dependent mammalian cells. We developed a novel microcarrier by binding ProNectin F, an artificial cell adhesive protein synthesized by genetically engineered Escherichia coli to a polyacrylic superabsorbent polymer. The microcarrier is characterized by containing no animal-derived components. The serum-free culture of Vero cells for vaccine production using the microcarrier increased the number of Vero cells by approximately 30% compared with the existing dextran beads coated with porcine Type I collagen, which resulted in approximately a 30% to 40% increase in the infectivity titer of the Sabin 2 strain of poliovirus. These results suggested that the developed microcarrier should be unprecedented in permitting high-yield vaccine production by means of a serum-free culture. 相似文献
125.
If a large amount of the future penetration of PV systems is imaged, it is likely that they densely concentrate in a certain area. It may not be a simple aggregation of individually optimized system, but a different system image may result by the total optimization of an area. The author frames this new question as the problem of “Areal Evolution” or “PV-AREA”. The following two cases are dealt with and their concrete concepts are given: (1) PV systems for community, (2) global-scale utilization of PV systems. 相似文献
126.
Norihiro Kawasaki Takashi Oozeki Kenji Otani Kosuke Kurokawa 《Solar Energy Materials & Solar Cells》2006,90(18-19):3356-3363
Short-time fluctuations in solar irradiance will become an important issue with regard to future embedded photovoltaic (PV) systems. However, when PV systems are intensively installed, fluctuation of total output in clustered PV systems is not remarkable because there is the smoothing effect of irradiance in certain areas. In this paper, a new estimation method of irradiance fluctuation, which is based on the combination of the Fourier transform and the wavelet transform methods, is described. 相似文献
127.
Akira Miyazaki Takayuki Yamazaki Taikan Suehara Toshio Namba Shoji Asai Tomio Kobayashi Haruo Saito Toshitaka Idehara Isamu Ogawa Yoshinori Tatematsu 《Journal of Infrared, Millimeter and Terahertz Waves》2014,35(1):91-100
Positronium is an ideal system for research on Quantum Electrodynamics (QED), especially in a bound state. A discrepancy of 3.9 standard deviations has been found between the measured hyperfine structure (Ps-HFS) and the QED predictions. This may be due to the contribution of unknown new physics or common systematic effects in previous measurements, in all of which the Zeeman effect was used. We propose a new method to directly measure the Ps-HFS using a high power gyrotron. We compare two resonators which have been developed to supply sufficient power to drive the direct transition, a Fabry-Pérot resonator and a ring resonator with a diffraction grating. We plan to perform first direct measurement of Ps-HFS within the next six months. 相似文献
128.
129.
Masaaki Suzuki Yves Maniette Yoshinori Nakata Takeshi Okutani 《Ceramics International》1993,19(6):407-413
The synthesis conditions of SiC ultrafine particles from SiH4 and C2H4 using a CO2 laser were studied and a comparison was made between SiH4---C2H4 and SiH2Cl2---C2H4 systems. Ultrafine SiC particles were synthesized by irradiating a SiH4 and C2H4 gas mixture with a CO2 laser at atmospheric pressure. SiC particles were obtained at a laser power of more than 0·92 kW/cm2.
The behavior of the reaction flame temperature and the extent of the laser light absorption by SiH4---C2H4 was different from that of SiH2Cl2---C2H4, although an abrupt temperature increase was observed in both cases. In the case of SiH4---C2H4 an abrupt increase in the laser light absorption was not observed, whilst it was observed in the case of SiH2Cl2---C2H4. This difference resulted from the difference in liability to form solid carbon particles. 相似文献
130.
T Xi M Sato A Nakamura Y Kawasaki T Umemura M Tsuda Y Kurokawa 《Canadian Metallurgical Quarterly》1994,28(4):483-490
The pharmacological characteristics of the 3-oxamethano-prostaglandin I1 compound (+)-methyl [2-[(2R,3aS,4R,5R,6aS)-octahydro-5-hydroxy-4- [(E)-(3S,5S)-3-hydroxy-5-methyl-1-nonenyl]-2-pentalenyl]etho xy] acetate (SM-10902, CAS 139403-31-9), a novel stable analogue of prostacyclin and its free acid, SM-10906, were studied. SM-10902 was rapidly deesterified to its free acid in rabbit and human serum. SM-10902 and SM-10906 exhibited antiplatelet potency against ADP-induced aggregation in rabbit and human platelets. In the presence of diisopropyl fluorophosphate, an esterase inhibitor, the antiplatelet activity of SM-10902 was markedly reduced, to much less than that of SM-10906. SM-10906 inhibited platelet aggregation induced by various inducers in several species and enhanced the cyclic AMP (cAMP) level in human platelets. These activities were nearly equal to those of prostaglandin (PG) E1 and less than those of PGI2. SM-10906 relaxed isolated rabbit mesenteric and bovine coronary arteries, and elevated the cAMP level in bovine coronary arteries. SM-10906 given intravenously exhibited a sustained reduction in blood pressure based on vasodilation in ganglion-blocked, angiotensin II-supported rats. SM-10902 applied to the guinea-pig auricles increased the skin temperature, but SM-10906 and PGI2 showed no such effect. In conclusion, SM-10902, which is considered to be a prodrug of SM-10906, was suggested to exert its anti-platelet and vasodilator activities through the increase of cAMP. Since SM-10902 penetrates well into the skin, it may be useful as an external preparation to improve peripheral circulatory insufficiency. 相似文献