全文获取类型
收费全文 | 1418篇 |
免费 | 22篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 81篇 |
综合类 | 2篇 |
化学工业 | 419篇 |
金属工艺 | 46篇 |
机械仪表 | 33篇 |
建筑科学 | 21篇 |
能源动力 | 97篇 |
轻工业 | 125篇 |
水利工程 | 9篇 |
石油天然气 | 1篇 |
无线电 | 117篇 |
一般工业技术 | 256篇 |
冶金工业 | 43篇 |
原子能技术 | 45篇 |
自动化技术 | 148篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 20篇 |
2020年 | 13篇 |
2019年 | 23篇 |
2018年 | 14篇 |
2017年 | 14篇 |
2016年 | 27篇 |
2015年 | 18篇 |
2014年 | 48篇 |
2013年 | 105篇 |
2012年 | 80篇 |
2011年 | 80篇 |
2010年 | 72篇 |
2009年 | 91篇 |
2008年 | 79篇 |
2007年 | 63篇 |
2006年 | 54篇 |
2005年 | 52篇 |
2004年 | 37篇 |
2003年 | 49篇 |
2002年 | 42篇 |
2001年 | 25篇 |
2000年 | 33篇 |
1999年 | 37篇 |
1998年 | 35篇 |
1997年 | 16篇 |
1996年 | 29篇 |
1995年 | 15篇 |
1994年 | 17篇 |
1993年 | 20篇 |
1992年 | 22篇 |
1991年 | 15篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 15篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 13篇 |
1980年 | 16篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1976年 | 5篇 |
1968年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有1443条查询结果,搜索用时 0 毫秒
71.
Yasuteru Sibamoto Taisuke Yonomoto Yoshinari Anoda Yutaka Kukita 《Nuclear Engineering and Design》2000,201(1):83
A density-stratified countercurrent flow was investigated to obtain data necessary to develop a physical model on a thermally stratified flow in a horizontal leg of a pressurized water reactor (PWR). The experiments were conducted at atmospheric pressure and temperature using fresh water and NaCl solution with a non-dimensional density ratio of up to 1.2. The emphasis was placed on measurements of velocity and concentration profiles near the interface between the two fluid layers. Measured mean velocity and concentration profiles were fitted consistently using the Monin–Obukhov similarity theory, which are well-known outcomes for stratified turbulent shear flow. The interfacial friction and entrainment coefficients obtained from the fitted profiles agreed well with existing results in literature, confirming the applicability of the Monin–Obukhov theory. Furthermore, a new empirical correlation was proposed for the prediction of a mixing layer thickness. 相似文献
72.
Masaaki Takashige Terutaro Nakamura Yutaka Aikawa Min Su Jang 《Ferroelectrics Letters Section》1982,44(3):77-84
The effect of isothermal annealing of amorphous PbTiO3 at a temperature below the crystallization temperature, Tcrys, has been investigated. Time dependent dielectric constant in the annealing process has been observed. From the experimental results, both the existence of the glass transition temperature, Tg, and the steadiness of dielectric constant at room temperature have been established. 相似文献
73.
One difficulty in analyzing the state of filament in the dry spinning process is that in the boundary conditions required to solve the equations of mass, momentum and energy which are derived on the consideration of balance with respect to infinitesimally small element are not given a priori. The equations which include these boundary conditions in themselves are derived by considering mass, momentum, and energy balances with respect to the entire cross section of filament. These additional macroscopic equations are simplified to a great extent by assuming the flat velocity profile through the cross section of filament. Besides, in the steady state, these macroscopic equations are modified to give the equations of average solvent content, spinning tension, cross-sectional area, and average temperature. When the spinning conditions are given and the physical constants are measured for a given polymer and solvent system, it becomes possible to calculate the state of filament by solving these microscopic and macroscopic equations simultaneously without resorting to actual spinning. 相似文献
74.
Thanda Oo Hiroshi Kawasaki Yutaka Ohsawa Katsushi Ikeuchi 《Machine Vision and Applications》2007,18(1):17-24
This paper presents an optimal method for the separation of reflected and transparent layers from real-world scene images.
Whereas past research has been applied to indoor environments and static cameras, our technique can be used for outdoor scenes
and motion cameras. The method is based on spatio-temporal analysis, especially using epipolar plane images (EPI). The edge
and color information of EPI has been used to segment the areas on EPIs efficiently and separate the reflected and transparent
layers. This method can be used for refining building textures by removing reflections from captured images for the purpose
of city modeling. 相似文献
75.
Introducing the ways of cultivating mental balance, B. A. Wallace and S. L. Shapiro (see record 2006-12925-003) attempted to build bridges between Buddhism and psychology. Their systematic categorization of Buddhist teachings and extensive review of empirical support from Western psychology are valuable for future study. However, it remains a matter of concern that some more profound parts of Buddhist philosophy can be disregarded by focusing only on practical aspects of Buddhism within the context of mental health. In this comment, the authors briefly address four substantial themes to be considered: reality, identity, causality, and logicality. They suggest that the way to interpret Buddhism as techniques for well-being would certainly be viable in encouraging the study of Buddhist teachings in psychology. Yet, such attempts should not result in superficial imports and applications of Buddhist practices but give due weight to the deeper philosophical issues to build more solid bridges between Buddhism and psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
76.
Kimihiro Yamanaka Yutaka Tsukada Katsuaki Suganuma 《Microelectronics Reliability》2007,47(8):1280-1287
This paper aims to understand the solder bump electromigration phenomenon in the Cu/Sn–3Ag–0.5Cu/Cu system. A temperature of 453 K with a current density of 10 kA/cm2 was applied. A void nucleated at the highest current density point at the cathode. As the void grew along the cathode side, a solder depletion occurred on the opposite side of the electron entry point, resulting in an open failure. A unique purposely-designed 3D model simulation methodology provides a good understanding of the void nucleation and growth behavior. The temperature of the solder joint during the electromigration test was measured successfully by the resistance change in the junction line between the two joints. 相似文献
77.
Takeshi Ando Eiichi Ohki Yasutaka Nakashima Yutaka Akita Hiroshi Iijima Osamu Tanaka 《Advanced Robotics》2013,27(15):1727-1746
The article describes the development of a gait phase time-based split-belt treadmill measurement system. Conventional methods of measuring gait phase, such as the foot switch and force plate, require significant preparation and are costly. In this article, we propose a simple, cheap, and accurate gait phase measurement system that utilizes only the treadmill motor current value. Comparison of this algorithm with conventional methods reveals that the proposed algorithm is as accurate as the foot switch. Moreover, the proposed algorithm can estimate stance phase within a 0.2?s error of the measured value of the force plate in most cases (four out of five healthy subjects). This accuracy is higher than that of the foot switch which is widely used in the clinical field. 相似文献
78.
A single loop electrochemical potentiokinetic reactivation test method has been developed for alloy 600 that produces good passivation on all the surfaces, good etching during the reactivation scan and no appreciable pitting. It is able to quantify and discriminate between samples with a wide range of degree of sensitization. The Pa value correlates well with the minimum level of chromium in the depletion regions at the grain boundaries. It has been shown that the width of the attacked regions is much larger than the width of chromium depletion regions and it does not show any direct correlation with either depth or width or with a volume parameter of chromium depletion regions. It has been shown that the chromium carbides are not attacked during the test and that the intragranular regions attacked during the test are the sites of chromium carbides in the grain matrix. A modified Pa parameter is shown to be sensitive down to 7.5 wt% chromium in the depletion regions and indicates that the intragranular carbides have shallower depletion profiles than those at grain boundaries. Comparison of the results of the single loop and the double loop tests showed a good correlation. 相似文献
79.
Scintillation properties of Tm-doped Lu3Al5O12 single crystals 总被引:1,自引:0,他引:1
Makoto Sugiyama Yutaka Fujimoto Takayuki Yanagida Daisuke Totsuka Yuui Yokota Akira Yoshikawa 《Optical Materials》2011,34(2):439-443
Using the micro-pulling-down (μ-PD) method, Tm-doped Lu3Al5O12 (Tm:LuAG) single crystals were grown to examine their scintillation properties. In transmittance spectra, they exhibited about 80% transparency in the wavelengths longer than 320 nm and five absorption lines due to Tm3+ 4f–4f transitions were observed. 241Am α-ray excited radioluminescence spectra were measured and intense 4f–4f emission peaks were observed with the host emission. When excited by 137Cs γ-Ray to obtain pulse height spectra, Tm 1% doped LuAG showed the highest light yield coupled with a photomultiplier (PMT) or a silicon avalanche photodiode (Si-APD). The light yield was estimated to be 5800 and 7300 photons/MeV for PMT and Si-APD, respectively. Decay time profiles consist of two exponential components and the fast and slow components are considered to be attributed to the host and the combination of the host and Tm3+ 4f–4f emission, respectively. 相似文献
80.
A new optical CO2 sensor based on the overlay of the CO2 induced absorbance change of pH indicator dye α-naphtholphthalein with the fluorescence of tetraphenylporphyrin (TPP) was developed. The observed luminescence intensity from TPP at 655 nm increased with increasing the CO2 concentration. The ratio I100/I0 values of the sensing films consisting of α-naphtholphthalein in ethyl cellulose layer and TPP in polystyrene layer, where I0 and I100 represent the detected luminescence intensities from a layer exposed to 100% nitrogen and 100% CO2, respectively, that the sensitivity of the sensor, are more than 53.9. The response and recovery times of the sensing films consisting of α-naphtholphthalein in ethyl cellulose layer and TPP in polystyrene layer were less than 5 s for switching from nitrogen to CO2, and for switching from CO2 to nitrogen. The signal changes were fully reversible and no hysterisis was observed during the measurements. The highly sensitive optical CO2 sensor based on fluorescence intensity changes of TPP due to the absorption change of α-naphtholphthalein with CO2 was achieved. 相似文献