全文获取类型
收费全文 | 485篇 |
免费 | 12篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 23篇 |
综合类 | 1篇 |
化学工业 | 151篇 |
金属工艺 | 21篇 |
机械仪表 | 7篇 |
建筑科学 | 11篇 |
能源动力 | 22篇 |
轻工业 | 30篇 |
水利工程 | 1篇 |
无线电 | 19篇 |
一般工业技术 | 155篇 |
冶金工业 | 4篇 |
原子能技术 | 22篇 |
自动化技术 | 32篇 |
出版年
2022年 | 14篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 15篇 |
2013年 | 23篇 |
2012年 | 22篇 |
2011年 | 35篇 |
2010年 | 15篇 |
2009年 | 35篇 |
2008年 | 22篇 |
2007年 | 23篇 |
2006年 | 25篇 |
2005年 | 17篇 |
2004年 | 12篇 |
2003年 | 16篇 |
2002年 | 18篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 15篇 |
1997年 | 5篇 |
1996年 | 11篇 |
1995年 | 4篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 1篇 |
1989年 | 9篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1971年 | 2篇 |
1970年 | 3篇 |
排序方式: 共有499条查询结果,搜索用时 15 毫秒
131.
132.
The normalized stress intensity factor (SIF) range of an inner-surface circumferential crack in a thin to thick-walled finite-length cylinder under thermal striping was considered in this paper. The edges of the cylinder were rotation-restrained and the outer surface was adiabatically insulated. The inner surface of the cylinder was heated by a fluid with sinusoidal temperature fluctuation. An analytical temperature solution for the problem and our semianalytical numerical SIF evaluation method for the crack were combined and, as a result, it was shown that the transient SIF solution can be expressed in a generalized form by dimensionless parameters such as mean-radius-to-wall-thickness ratio, Biot number, normalized striping frequency, and Fourier number. Finally, normalized SIF ranges for the first cycle and steady state were given for these dimensionless parameters in tables for mean-radius-to-wall-thickness ratio of 10, 5, and 1. 相似文献
133.
Harumi Yokokawa Natsuko Sakai Teruhisa Horita Katsuhiko Yamaji Yueping Xiong Takanori Otake Hiroo Yugami Tatsuya Kawada Junichiro Mizusaki 《Journal of Phase Equilibria and Diffusion》2001,22(3):331-338
Phase diagram calculations that were made previously for the ZrO2-MO
m/2 (m = 2, 3, 4) systems and for the ZrO2-YO1.5-MO
m/2 (M = transition metals) systems have been extended to the ZrO2-YO1.5-CeO2(-CeO1.5) system to make an attempt to explain (1) thermogravimetric (TG) results as a function of oxygen potential, (2) electronic
conductivity as a function of oxygen potential, and (3) a miscibility gap observed in air. The interaction parameters for
the CeO2-CeO1.5-YO1.5 system were obtained from the reported oxygen nonstoichiometry in CeO2−x
and rate earth doped ceria, (Ce,RE)O2−δ
. The interaction parameters for the ZrO2-CeO2 subsystem were obtained so as to reproduce the observed miscibility gap at 1273 K. Those thermodynamic properties can reproduce
consistently the experimental behaviors of the electronic conductivity and the TG results in the (Zr1−x
Ce
x
)0.8Y0.2O1.9 solid solutions; these indicate the enhancement of reduction of CeO2. 相似文献
134.
Wataru Mizubayashi Naoki Yasuda Kenji Okada Hiroyuki Ota Hirokazu Hisamatsu Kunihiko Iwamoto Koji Tominaga Katsuhiko Yamamoto Tsuyoshi Horikawa Toshihide Nabatame Hideki Satake Akira Toriumi 《Microelectronics Reliability》2005,45(7-8):1041-1050
The carrier conduction and the degradation mechanism in n+gate p-channel metal-insulator-semiconductor field-effect-transistors with HfAlOX (Hf: 60 at.%, Al: 40 at.%)/SiO2 dielectric layers have been investigated using carrier separation method. Since gate current depends on substrate bias and both electron and hole currents are independent of temperature over the range of 25–150 °C, the conduction mechanism for both currents is controlled by a tunneling process. As the interfacial SiO2 layer (IL) thickness increases in a fixed high-k layer thickness (Thigh-k), a dominant carrier in the leakage current changes from hole to electron around 2.2-nm-thick IL. This is due to an asymmetric barrier height for electrons and holes at the SiO2/Si interface. On the contrary, in the case of a fixed IL thickness of 1.3 nm, the hole current is dominant in the leakage current, regardless of Thigh-k. It is shown that the dominant carrier in the leakage current depends on the structure of the high-k stack. Both electron and hole currents for the stress-induced-leakage-current (SILC) state increase slightly relative to the initial currents, which means that the trap generation in the high-k stack occurs near both the conduction band edge of n+poly-Si gate and the valence band edge of Si substrate. The electron current at soft breakdown (SBD) state dramatically increases over that for the SILC state, while the hole currents for both the SILC state and SBD are almost the same. This indicates that the defect sites generated in the high-k stack after SBD are located at energies near the conduction band edge of n+poly-Si gate. Both the defect generation rate and the defect size in the HfAlOX/SiO2 stacks are large compared with those in SiO2. It is inferred that, in high-k dielectric stack, the defect generation mainly occurs in the high-k side rather than the IL side, and the defect size larger than the case of SiO2 could be related to a larger dielectric constant of the high-k layer. 相似文献
135.
136.
This paper deals with crack energy density (hereafter CED) as a possible fracture parameter in piezoelectricity under arbitrary electric boundary conditions on a notch-like crack surface. The definitions of CED and its derivatives are given first under exact boundary condition. Next, their path independent integrals are also derived and their approximate expressions are discussed under some restrictions on the crack surfaces. It is found that electrical terms along the notch-like crack surface do not vanish unlike in the case of impermeable crack. Then, we introduce evaluation methods of CED, and, with the help of the results of finite element analyses (FEA), we closely examine how electric boundary conditions along the notch surface and initial notch width influence CED and its derivatives. It is shown from the FEA results that because of the difficulties of computing path integral terms along the notch-like crack tip in the path independent expressions, the evaluation by the definitions of CED and its derivatives is preferable and more convenient than the evaluation of their path independent expressions. It is also found that all the parameters are significantly affected by both permittivity inside the electric inclusion and root radius of the notch. Finally, the possibility of mechanical CED as a governing fracture parameter is discussed. 相似文献
137.
Sigurd Wenner Katsuhiko Nishimura Kenji Matsuda Teiichiro Matsuzaki Dai Tomono Francis L. Pratt Calin D. Marioara Randi Holmestad 《Metallurgical and Materials Transactions A》2014,45(12):5777-5781
The precipitate microstructure and vacancy distribution in Al-Mg-Si alloys with different amounts of solute and different heat treatments were investigated by transmission electron microscopy and muon spin relaxation measurements. A high amount of vacancies is normally present in Al-Mg-Si alloys as these bind to atomic clusters. We observe these vacancies to leave the material not before over-aging at very high temperatures such as 623 K (350 °C), meaning that vacancies do not bind to incoherent over-aged precipitates. For samples only stored at room temperature after solution heat treatment, a reduction of muon trapping was found at a temperature of 140 K (?133 °C) when reducing the amount of solute in the alloy. This might be connected to a lower number density of Cluster (1), which contrary to Cluster (2) do not nucleate precipitates upon further aging of the material. 相似文献
138.
A model of IASCC initiation stress for bolts of core internals in pressurized water reactors was developed considering differences in material property changes due to irradiation and material conditions. Assuming that IASCC initiation was controlled by grain boundary composition and yield strength, these values for each specimen of post-irradiation IASCC initiation tests were calculated by physical kinetic models considering dose rate, temperature, material composition and surface hardening. Then, correlations of grain boundary composition and yield strength with IASCC initiation stress were determined. The model predicted that the IASCC initiation stress became lower with dose and was lower for higher temperature, lower flux and higher surface hardening level. 相似文献
139.
Katsuhiko Takahashi 《国际生产研究杂志》2013,51(18):4317-4337
In an effort to achieve agile control in a just-in-time (JIT) environment, reactive JIT ordering systems have been proposed for multistage production systems with unstable changes in demand. In reactive JIT ordering systems, the time series data for the demand are monitored, and unstable changes in demand are detected using statistical control charts. Then, in these systems, the number of Kanbans and the buffer size at each stage are adjusted as a response to the detected unstable changes. Recently, an adaptive Kanban system based on inventory levels was proposed and applied to unstable demand conditions. However, its performance has not yet been analysed and compared with the other reactive system. Therefore, the first purpose of this paper is to analyse and compare the performance of the reactive Kanban systems, both the control chart-based and the inventory-based systems. In addition to comparing their performance, as the second purpose, a new inventory-based system is proposed. In the proposed system, the time series data for the demand is not monitored, but instead the inventory level of a product is monitored to detect unstable changes in demand, and the number of Kanbans is adjusted as a response to these detected unstable changes. The performance of the proposed system is investigated and compared with those of the previous systems by using simulation experiments that model unstable demand conditions. 相似文献
140.