全文获取类型
收费全文 | 959篇 |
免费 | 21篇 |
国内免费 | 4篇 |
学科分类
工业技术 | 984篇 |
出版年
2023年 | 3篇 |
2021年 | 18篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 22篇 |
2017年 | 14篇 |
2016年 | 27篇 |
2015年 | 5篇 |
2014年 | 23篇 |
2013年 | 69篇 |
2012年 | 32篇 |
2011年 | 56篇 |
2010年 | 57篇 |
2009年 | 50篇 |
2008年 | 51篇 |
2007年 | 43篇 |
2006年 | 48篇 |
2005年 | 29篇 |
2004年 | 36篇 |
2003年 | 36篇 |
2002年 | 37篇 |
2001年 | 24篇 |
2000年 | 17篇 |
1999年 | 16篇 |
1998年 | 18篇 |
1997年 | 13篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 13篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 11篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1980年 | 15篇 |
1979年 | 12篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1970年 | 3篇 |
1967年 | 2篇 |
排序方式: 共有984条查询结果,搜索用时 15 毫秒
21.
The rate of evaporation of monodisperse water droplets was first evaluated by solving numerically the modified Maxwell equation, assuming the cellular model for a droplet clouds. The results are discussed in comparison with those for a single isolated droplet, which can be obtained analytically. The critical conditions for the droplet cloud to be stable are then evaluated as a function of droplet number concentration, droplet size and initial conditions of the surrounding air. Secondly, the equilibrated system, where a water droplet cloud is steadily mixed with unsaturated air, was analysed on the basis of enthalpy and material balance of the system to evaluate the total volume change of the droplets. Some of these analyses were verified by experiment, using an ultramicroscopic technique which is useful for droplet size analysis. 相似文献
22.
Xinwen Zhu Tetsuo Uchikoshi Tohru S. Suzuki Yoshio Sakka 《Journal of the American Ceramic Society》2007,90(3):797-804
The roles of polyethylenimine (PEI) in the hydrolysis and dispersion properties of aqueous Si3 N4 suspensions were studied in terms of the hydrolysis, adsorption, electrokinetic, and rheological measurements. It was found that the pH change of the suspensions in the acidic environment could be minimized in the presence of ≥0.5 dwb% PEI. The ammonia and oxygen measurements suggest that this phenomenon is primarily attributed to the buffer mechanism generated by the ionized PEI, instead of the protection mechanism. The constant pH enables the suspensions to retain a better stability with time at acidic pH. The adsorption of PEI on Si3 N4 is a high-affinity type at highly basic pH, but is a low-affinity type at acidic pH. As the PEI amount increases, the adsorption shifts the isoelectric point (IEP) of Si3 N4 from pH 5.9 to pH ∼11 until complete coverage is attained. The stability of Si3 N4 suspensions is found to depend strongly on the saturated adsorption of PEI, which is as a function of the pH and PEI amount. Once the saturated adsorption limit is reached, the excess free PEI molecules become more detrimental to the stability with increased solid loading. The stabilization mechanisms of Si3 N4 suspensions by PEI were discussed in detail. 相似文献
23.
Yusaku Takita Jun-ichi Moriyama Hiroyasu Nishiguchi Tatsumi Ishihara Fusakazu Hayano Tetsuo Nakajo 《Catalysis Today》2004,88(3-4):103-109
Activity for hydrolysis of CCl2F2 (CFC12) on various metal sulfate was investigated. Zr(SO4)2 was found to be the most active while FeSO4, Cr2(SO4)3, Al2(SO4)3, La2(SO4)3 and Ce2(SO4)3 had intermediate activity. MnSO4, CoSO4, and MgSO4 showed low activity and SrSO4, CaSO4, and BaSO4 had even less activity. The major carbon containing product was CO2 and small amount of CClF3 and CO were formed over several sulfates. The crystal structure of the sulfates was stable during decomposition of CCl2F2, and the conversion reached a steady state after initial decrease at 275 °C over Zr(SO4)2 catalyst. The concentration of surface hydroxyl was larger than that over AlPO4-based catalysts and a reaction mechanism similar to that over AlPO4-based catalysts was proposed. 相似文献
24.
In order to develop an energy-saving copper recycling process from wastes, electrochemical measurements were conducted in ammoniacal alkaline solutions containing Cu(I) ions and an ammonium salt of sulfate, chloride or nitrate. The results of each system were then compared. The polarization measurements suggested that the voltage required for the electrode process is lower in the chloride and nitrate systems than that in the sulfate system. The cathode current efficiency during the copper electrodeposition varied from 39 to 97% and increased with current density in the chloride and sulfate systems. In the nitrate system, the lowest cathode current efficiency of 30% was observed because of nitrate ion reduction. Based on these results, the power consumption required for the electrowinning stage of the copper recycling process was calculated. Among these three systems, the chloride system showed the lowest power consumption of 500 kWh t−1 at the current density of 200 A m−2, which is about 25% of the conventional copper electrowinning process from a copper sulfate-sulfuric acid solution. 相似文献
25.
In this paper, we propose a reality-oriented augmentation approach to support training activities. The approach aims at adding new value and playful features to traditional training environments with keeping their original look-and-feel. For example, a game monitoring service enables to automatically record game events so that players can review a gaming process and strategy for soul-searching, or replay most impressive scenes to share the experience with others after the game finishes. Even several services are running on background, digital devices and services are seamlessly integrated to the game environment in unobtrusive way so that players can concentrate on training as usual. The concept can be applied to both traditional games (e.g., poker and the game of Go) and non-gaming activities (e.g., calligraphy and drumming). We developed four case studies on the concept: Augmented Reality Go, EmoPoker, Augmented Calligraphy and AR Drum Kit. We discuss design issues in the reality-oriented augmentation process based on user study results. 相似文献
26.
By means of SR X-ray diffractometry, cooperative Jahn-Teller distortion as a structural phase transformation of the first kind is directly confirmed by a splitting of Laue spots. It is understood that the degenerate ground state of a nonmagnetic doublet (3) of Ho3+ in a cubic Ho-elpasolite, Fm3m(O
h
5
), at least above 600 mK, is lifted up by a distortion below 150 mK, which was predicted by a splitting of the NQR spectrum and anomalies in the specific heat and magnetic susceptibility. This structural transformation shows not only the lowest transition temperature up to now, but also the greatest hysteresis specified by a Schottky-type excitation. The magnitude of the relative distortion (1/1) has been roughly estimated to be on the 2.0 · 10–3 order of magnitude, which is much larger than the predicted value obtained from a point charge approximation. The pecularities of this transition are discussed from the viewpoint that the general theory of a structural transformation, established convincingly at high temperatures could not be easily applied. 相似文献
27.
Takayuki Goto Takao Watanabe Kyoichi Kinoshita Azusa Matsuda Masafumi Sera Tetsuo Fukase 《Journal of Low Temperature Physics》1996,105(3-4):401-406
Cu-NMR spectra and the nuclear spin-lattice relaxation rate T
1
-1
have been studied intensively on the bilayer type high-Tc cuprate La1.89Ca1.11Cu2O6+ (La2126). The resonance line shift showed a monotonic decrease with lowering temperature in the normal state, indicating that this compound belongs to the lightly-doped region. The Curie-Weiss temperature dependence of (T1T)–1 in the normal state shows that the pseudo spin-gap does not always exist in the light-doped bilayer systems. 相似文献
28.
Hiroyuki Fujishiro Manabu Ikebe Masayuki Yagi Kiminari Nakasato Yuzo Shibazaki Tetsuo Fukase 《Journal of Low Temperature Physics》1996,105(3-4):981-986
The thermal conductivity of high density La2–xMxCuO4 (M=Ba, Sr) sintered materials was measured between 15K and 150K for the various concentrations of Ba and the phonon thermal conductivity was analyzed comparing with that of Nd2–xCexCuO4. The pretty large value for pure La2CuO4 was drastically diminished by substituting La by a small amount of Ba atoms especially at low temperatures. It was found that a new type of the phonon scattering center such as a two-level tunneling must be taken account of in order to explain the observed reduction. 相似文献
29.
Fusaomi Nagata Takanori Mizobuchi Shintaro Tani Tetsuo Hase Zenku Haga Keigo Watanabe Maki K. Habib 《Artificial Life and Robotics》2010,15(1):106-110
In this article, a new desktop orthogonal-type robot, which has the capacity of stick-slip motion control based on cutter
location data, is presented for lapping small metallic molds with a curved surface. The robot consists of three single-axis
devices with a high position resolution of 1 μm. A thin wooden stick tool with a ball-end shape is attached to the tip of
the z-axis. In order to improve the lapping performance, a novel stick-slip motion control method is developed in the control system.
The small stick-slip motion is orthogonally generated in the direction of the tool’s movement. The effectiveness of stick-slip
motion control is examined through an actual lapping test of an LED lens cavity. 相似文献
30.
Tetsuo Yamada Naoyuki Mizuhara Hisashi Yamamoto Masayuki Matsui 《Computers & Industrial Engineering》2009,56(3):1113-1125
For sustainable manufacturing, manufacturers should construct and design inverse manufacturing systems consisting of assembly and disassembly systems. The sorting process in the disassembly system is the first process of the whole inverse manufacturing system. Therefore, it can become a bottleneck and decrease the productivity of the whole inverse manufacturing systems.This study focuses on a disassembly system with reverse blocking in a sorting process [Yamada, T., & Matsui, M. (2003). Disassembly production systems and its design issues. Reprints of Japan Industrial Management Association, Spring meeting, Chofu, Japan, May, 144–145 (in Japanese)]. It generalizes the queuing model and discusses the performance of the disassembly system by mathematical and numerical analysis. First, the sorting process with reverse blocking is generally modeled as a queuing system. Next, the stationary state equations of the system are formulated, and the objective function is set as the throughput. Finally, the system performance is discussed by mathematical and numerical analysis in cases of a different number of stations and buffers, and also an example of the system design is shown and discussed in view of the busy rate, blocking probability and throughput. 相似文献