全文获取类型
收费全文 | 915篇 |
免费 | 17篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 80篇 |
综合类 | 6篇 |
化学工业 | 211篇 |
金属工艺 | 49篇 |
机械仪表 | 28篇 |
建筑科学 | 15篇 |
矿业工程 | 1篇 |
能源动力 | 36篇 |
轻工业 | 47篇 |
水利工程 | 4篇 |
石油天然气 | 3篇 |
无线电 | 66篇 |
一般工业技术 | 182篇 |
冶金工业 | 121篇 |
原子能技术 | 38篇 |
自动化技术 | 49篇 |
出版年
2022年 | 8篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 12篇 |
2018年 | 19篇 |
2017年 | 7篇 |
2016年 | 13篇 |
2015年 | 7篇 |
2014年 | 20篇 |
2013年 | 49篇 |
2012年 | 38篇 |
2011年 | 49篇 |
2010年 | 29篇 |
2009年 | 31篇 |
2008年 | 41篇 |
2007年 | 43篇 |
2006年 | 23篇 |
2005年 | 31篇 |
2004年 | 30篇 |
2003年 | 27篇 |
2002年 | 28篇 |
2001年 | 26篇 |
2000年 | 27篇 |
1999年 | 15篇 |
1998年 | 39篇 |
1997年 | 40篇 |
1996年 | 26篇 |
1995年 | 20篇 |
1994年 | 19篇 |
1993年 | 21篇 |
1992年 | 5篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 11篇 |
1985年 | 14篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 15篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 12篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1973年 | 7篇 |
1972年 | 3篇 |
排序方式: 共有936条查询结果,搜索用时 31 毫秒
91.
Akimoto T. Murai I. Kato S. Chaki S. Shoji I. Ogawa Y. 《IEEE transactions on nuclear science》1990,37(5):1594-1598
The design and feasibility of a simple and practical system for measuring two-parameter signals is reported. A dual-parameter multichannel pulse-height analyzer (MCA) which uses two central processing units (CPUs) is developed and designed. One computer (master computer) controls the other computer (slave computer), and also displays, records, and analyzes the data. The slave computer controls two analog-to-digital converters (ADCs), collects the dual-parameter data, and transfers the collected data to the master computer. Three methods of data transfer between the two CPUs are examined and discussed. The count capacity at the data collection by the slave computer is 216-1/ch (2-B-long data), and this is expanded to 232-a/ch (4-B-long data) at the master computer. The data are analyzed and at any time stored in the storage apparatus by the dual CPU system. The system demonstrates stable operation over long measurement periods 相似文献
92.
We report a novel porous fluorinated polyimide membrane with a cylinder structure fabricated by a wet phase inversion process, which is formed by a ternary system, polyimide/solvent/water. The porous polyimide membranes consisted of a thin top porous layer and three‐dimensionally ordered cylinder micropores. The porous membrane‐forming solvents were N‐methylpyrrolidone containing nonsolvent additives such as alcohol, and the height and width of the cylinder structure were controlled by the solvents. Water fluxes through the porous polyimide membranes were measured using a stirred dead‐end filtration cell, and the fluxes of the porous membrane with the cylinder‐type structure were approximately three times greater than those of the membrane with the finger‐type structure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3016–3021, 2004 相似文献
93.
We propose a new surface charge method based on the continuity of electric flux passing through each partial area on the dielectric boundary. N partial areas divided on the boundary give the boundary equations for solving N unknown variables representing the surface charge density distribution. The electric flux is numerically calculated by integrating the normal component of electric flux density on each partial area. This method permits us to exclude the singularity of edge parts from the boundary equations because these parts do not contribute to the integration area. In this paper, we apply first‐order functions to simulate both triangular surface shape and charge density distribution on its surface as well. First, we have computed the electric field for a spherical dielectric under a uniform field. The calculated results show that the accuracy of the electric field at the spherical center is almost equal to the accuracy of the total surface area of the polygon which represents the sphere. Furthermore, this method has improved the accuracy of the field by about one order compared with the conventional surface charge methods. Second, we have computed the electric field for a dielectric human model under a uniform field. The calculated results demonstrates that the proposed method works well for a complicated shaped object with a dielectric constant greatly different from that of an ambient medium. © 2002 Scripta Technica, Electr Eng Jpn, 138(4): 10–17, 2002; DOI 10.1002/eej.1133 相似文献
94.
T Tokuda T Fukushima S Ikeda Y Sekijima S Shoji N Yanagisawa A Tamaoka 《Canadian Metallurgical Quarterly》1997,41(2):271-273
We report a case of pseudosarcomatous fibromyxoid tumor of the bladder in a 23-year-old man with a 2 month history of painless gross hematuria, which was studied by biphasic contrast-enhanced helical CT. CT demonstrated a 2 cm diameter polypoid enhancing mass in the anterior bladder wall. The lesion measured 103 and 91 HU on early and delayed images, respectively. Increased contrast enhancement was attributed to a histologically highly vascular myxoid stroma. 相似文献
95.
An experiment was performed to simulate an air‐cooling panel system for passive decay heat removal from a high‐temperature gas‐cooled reactor to investigate the performance of decay heat removal and the temperature distributions of components of the system. The experimental apparatus consisted of a pressure vessel 1 m wide and 3 m high. Nineteen simulated standpipes containing heaters with a maximum heating rate of 100 kW simulated residual heat of the core, and the cooling panels surrounded the pressure vessel. An analytical code (THANPACST2) was applied to the experimental data to investigate the validity of the analytical method and the model proposed. Under the conditions of helium gas at a pressure of 0.64 MPa and temperature of 514 °C in the pressure vessel, the predicted temperature distribution in the pressure vessel was estimated and was within ?10 to +50 °C as compared to the experimental data. The analysis indicated that the heat transferred to the cooling panel was 15.4% less than the experimental value. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(8): 665–677, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10061 相似文献
96.
Koichi OkadaShigemi Kohiki Suning Luo Daiichiro SekibaSatoshi Ishii Masanori MitomeAtsushi Kohno Takayuki TajiriFumiya Shoji 《Thin solid films》2011,519(11):3557-3561
Thin films of indium tin oxide (ITO) sputter-deposited by dc-plasma containing deuterium on glass substrate without any heat treatments exhibited gradual lowering in electrical resistivity with increasing the deuterium content [D2] in plasma gas by 1% and then demonstrated a jump in resistivity by further increase of [D2] than 1%. X-ray photoelectron spectroscopy revealed that hydroxyl-bonded oxygen in ITO grew continuingly with [D2]. Deuterium positioned at the interstitial site increased almost quantitatively with increasing [D2]. Rutherford backscattering spectroscopy showed gradual reduction in the oxygen content of ITO with increasing [D2] by 1% and then demonstrated an abrupt increase of the oxygen content with the increase of [D2] than 1%. The films with [D2] < 1% were oxygen deficient, but those with [D2] > 1% were excess of oxygen. The most oxygen deficient film of [D2] = 1% was the most conductive. Behavior in the resistivity with [D2] looks parallel to that in the oxygen content. A lower resistivity of the films corresponded well to oxygen vacancy rather than hydrogen interstitial. 相似文献
97.
98.
99.
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
100.