全文获取类型
收费全文 | 6867篇 |
免费 | 122篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 337篇 |
综合类 | 4篇 |
化学工业 | 1323篇 |
金属工艺 | 194篇 |
机械仪表 | 147篇 |
建筑科学 | 113篇 |
能源动力 | 190篇 |
轻工业 | 474篇 |
水利工程 | 30篇 |
石油天然气 | 6篇 |
无线电 | 625篇 |
一般工业技术 | 1208篇 |
冶金工业 | 1792篇 |
原子能技术 | 140篇 |
自动化技术 | 419篇 |
出版年
2023年 | 25篇 |
2022年 | 47篇 |
2021年 | 102篇 |
2020年 | 52篇 |
2019年 | 53篇 |
2018年 | 66篇 |
2017年 | 71篇 |
2016年 | 82篇 |
2015年 | 70篇 |
2014年 | 94篇 |
2013年 | 228篇 |
2012年 | 195篇 |
2011年 | 282篇 |
2010年 | 185篇 |
2009年 | 220篇 |
2008年 | 231篇 |
2007年 | 235篇 |
2006年 | 232篇 |
2005年 | 202篇 |
2004年 | 190篇 |
2003年 | 189篇 |
2002年 | 189篇 |
2001年 | 164篇 |
2000年 | 149篇 |
1999年 | 177篇 |
1998年 | 674篇 |
1997年 | 425篇 |
1996年 | 310篇 |
1995年 | 225篇 |
1994年 | 219篇 |
1993年 | 174篇 |
1992年 | 99篇 |
1991年 | 99篇 |
1990年 | 98篇 |
1989年 | 85篇 |
1988年 | 83篇 |
1987年 | 66篇 |
1986年 | 79篇 |
1985年 | 85篇 |
1984年 | 54篇 |
1983年 | 63篇 |
1982年 | 45篇 |
1981年 | 55篇 |
1980年 | 57篇 |
1979年 | 33篇 |
1978年 | 26篇 |
1977年 | 62篇 |
1976年 | 57篇 |
1975年 | 33篇 |
1973年 | 25篇 |
排序方式: 共有7002条查询结果,搜索用时 15 毫秒
1.
Effects of Winding Attachment Positions on Output Characteristics of Flux‐Modulating Synchronous Machines
下载免费PDF全文
![点击此处可从《Electrical Engineering in Japan》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hirofumi Aoki Tadashi Fukami Kazuo Shima Toshihiro Tsuda Mitsuhiro Kawamura 《Electrical Engineering in Japan》2015,191(3):40-49
The flux‐modulating synchronous machine (FMSM) is a new type of multipole SM with nonoverlapping concentrated armature and field windings on the stator. This paper compares the output characteristics of two FMSMs through finite element analysis (FEA) and experiments. In both of the FMSMs, the attachment positions of the armature and field windings are swapped. To determine the reason for the discrepancies in their output characteristics, unsaturated inductances were calculated using a d‐‐q equivalent circuit. In addition, the calculated results of the inductances were confirmed through a visualization of the leakage fluxes using FEA. The results of the study show that the synchronous inductance can be reduced by attaching the armature winding to the air‐gap side of the stator teeth and that the reduction leads to an increase in output power. 相似文献
2.
Akira Yamamoto Kentaro Teramura Saburo Hosokawa Tsunehiro Tanaka 《Science and Technology of Advanced Materials》2015,16(2)
The effect of SO2 gas was investigated on the activity of the photo-assisted selective catalytic reduction of nitrogen monoxide (NO) with ammonia (NH3) over a TiO2 photocatalyst in the presence of excess oxygen (photo-SCR). The introduction of SO2 (300 ppm) greatly decreased the activity of the photo-SCR at 373 K. The increment of the reaction temperature enhanced the resistance to SO2 gas, and at 553 K the conversion of NO was stable for at least 300 min of the reaction. X-ray diffraction, FTIR spectroscopy, thermogravimetry and differential thermal analysis, x-ray photoelectron spectroscopy (XPS), elemental analysis and N2 adsorption measurement revealed that the ammonium sulfate species were generated after the reaction. There was a strong negative correlation between the deposition amount of the ammonium sulfate species and the specific surface area. Based on the above relationship, we concluded that the deposition of the ammonium sulfate species decreased the specific surface area by plugging the pore structure of the catalyst, and the decrease of the specific surface area resulted in the deactivation of the catalyst. 相似文献
3.
Toshihiro Ogino 《Soils and Foundations》2021,61(1):175-184
Since the introduction of bender element tests to soil testing, the reliability of the estimated travel time has been the most serious problem. The author has previously shown a potential solution whereby removing the response of the bender element subsystem from the whole response could dramatically improve the accuracy of the travel time estimation. In order to lay the foundation for estimating the response of the bender element subsystem, this paper examines the correlation between the displacements of the element and the induced feedback signals by employing a self-monitoring element. The response of the self-monitoring element is modeled as a transfer function involving two internal transfer functions that relate the input signals to the displacements and the displacements to the feedback signals, respectively. Using a laser displacement sensor, the displacements are directly measured through the entire surface and reveal the three-dimensional bending motion of the element oscillating in both longitudinal and width directions. The feedback signals are similar to, but inconsistent with, the tip displacements, and an attempt is made to correct the feedback signals. Finally, a conclusion is given on the potential for estimating the response of the bender element subsystem using the self-monitoring element. 相似文献
4.
Tatsuro Tanaka Yoshifumi Maeda Shinji Yamamoto Toru Iwao 《Electrical Engineering in Japan》2019,207(1):15-23
The arc welding has been used in various welding methods because it is inexpensive and high in strength after welding. However, it is a problem that accidents such as collapse of the bridge occur because of the welding defects. The welding of low cost and high productivity is required without the welding defects. The pulsed TIG welding is inexpensive and capable of high‐quality welding. The electromagnetic force contributing to penetration changes because the transient response of arc temperature and iron vapor generated from anode occurs. However, the analysis of pulsed TIG welding with metal vapor has been elucidated only metal vapor concentration near anode with transient phenomenon and heat flux. Thus, the theoretical elucidation of penetration depth with control factor has not been researched. In this paper, the contribution of metal vapor mass at the periphery part of pulsed arc to the electromagnetic force in the weld pool is elucidated. As a result, the iron vapor mass at periphery part decreased with increasing the frequency. The iron vapor was stagnated at axial center within one cycle. The electromagnetic force to the penetration depth direction in weld pool increased at axial center. Therefore, the metal vapor mass at periphery part plays an important role for the electromagnetic force increment at axial center. 相似文献
5.
Tomonari Tanaka Ayane Matsuura Yuji Aso Hitomi Ohara 《Journal of Applied Glycoscience》2020,67(4):119
Glycopolymers have attracted increased attention as functional polymeric materials, and simple methods for synthesizing glycopolymers remain needed. This paper reports the aqueous one-pot and chemoenzymatic synthesis of four types of glycopolymers via two reactions: the β-galactosidase-catalyzed glycomonomer synthesis using 4,6-dimetoxy triazinyl β-D-galactopyranoside and hydroxy group-containing (meth)acrylamide and (meth)acrylate derivatives as the activated glycosyl donor substrate and as the glycomonomer precursors, respectively, followed by radical copolymerization of the resulting glycomonomer and excess glycomonomer precursor without isolating the glycomonomers. The resulting glycopolymers bearing galactose moieties exhibited specific and strong interactions with the lectin peanut agglutinin as glycoclusters. 相似文献
6.
Graded evolution of anisotropic microstructure during sintering from crystal-oriented powder compact
Shoko Baba Alexandre Maître Nicolas Pradeilles Guy Antou Nobuo Saito Satoshi Tanaka 《International Journal of Applied Ceramic Technology》2020,17(2):677-684
Anisotropic sintering, including shrinkage and grain growth, was examined for c-axis-oriented (Sr,Ca)2NaNb5O15 (SCNN) ceramics, which were prepared by colloidal processing under a magnetic field. In the c-axis-oriented SCNN powder compact, shrinkage and grain growth along the c-axis were higher than those along the a-axis. The anisotropic microstructural development was clearly associated with anisotropic sintering shrinkage. X-ray diffraction, scanning electron microscopy, and energy back scattering diffraction showed that the grain growth of oriented particles by including random grains contribute to the development of the oriented microstructure. Finally, the highly crystal-oriented SCNN ceramics with a densified microstructure were obtained through anisotropic sintering. These results clearly showed the potential to develop a well-defined anisotropic microstructure during sintering by designing and controlling the particle packing structure in a powder compact. 相似文献
7.
8.
9.
NM Forones M Tanaka D Machado JB Falc?o M Giovanoni 《Canadian Metallurgical Quarterly》1997,34(1):3-6
Female SJL mice are more susceptible than male mice to experimental autoimmune encephalomyelitis (EAE) induced by myelin basic protein (MBP)-specific T lymphocytes. In the present study, we examined mechanisms involved in this gender-related difference in disease susceptibility. MBP-specific T lymphocytes derived from spleens of males during the effector phase of adoptive EAE produced significantly higher levels of IL-10, an anti-inflammatory cytokine in EAE. A protective effect of testosterone was then shown. Females implanted with dihydrotestosterone pellets demonstrated a significantly less severe course of EAE as compared with females implanted with placebo pellets. Finally, MBP-specific T lymphocytes derived from dihydrotestosterone-implanted females produced significantly higher levels of IL-10 than those from placebo. Together these data indicate that testosterone exerts a protective effect in EAE that is mediated at least in part by enhanced production of IL-10 by autoantigen-specific T lymphocytes. 相似文献
10.