全文获取类型
收费全文 | 818篇 |
免费 | 24篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 40篇 |
综合类 | 3篇 |
化学工业 | 278篇 |
金属工艺 | 28篇 |
机械仪表 | 19篇 |
建筑科学 | 15篇 |
能源动力 | 38篇 |
轻工业 | 108篇 |
石油天然气 | 3篇 |
无线电 | 42篇 |
一般工业技术 | 172篇 |
冶金工业 | 18篇 |
原子能技术 | 22篇 |
自动化技术 | 63篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 19篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 21篇 |
2015年 | 20篇 |
2014年 | 22篇 |
2013年 | 50篇 |
2012年 | 39篇 |
2011年 | 51篇 |
2010年 | 37篇 |
2009年 | 35篇 |
2008年 | 56篇 |
2007年 | 46篇 |
2006年 | 37篇 |
2005年 | 30篇 |
2004年 | 27篇 |
2003年 | 29篇 |
2002年 | 19篇 |
2001年 | 15篇 |
2000年 | 6篇 |
1999年 | 18篇 |
1998年 | 10篇 |
1997年 | 15篇 |
1996年 | 15篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 24篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有849条查询结果,搜索用时 15 毫秒
71.
Yoshinori Nishida Norihisa Izawa Yukio Kuramasu 《Metallurgical and Materials Transactions A》1999,30(3):839-844
Separation of matrix metals in composites was tried on alumina short fiber-reinforced aluminum and 6061 alloy composites and
SiC whisker-reinforced 6061 alloy composite for recycling. It is possible to separate molten matrix metals from fibers in
the composites using fluxes that are used for melt treatment to remove inclusions. About 50 vol pct of the matrix metals was
separated from the alumina short fiber-reinforced composites. The separation ratio of the matrix from the SiC whisker-reinforced
6061 alloy composite was low and about 20 vol pct. The separation mechanism was discussed thermodynamically using interface
free energies. Since the flux/fiber interface energy is smaller than the aluminum/fiber interface energy, the replacement
of aluminum with fluxes in composites takes place easily. Gases released by the decomposition of fluxes act an important role
in pushing out the molten matrix metal from the composite. The role was confirmed by the great amount cavity formed in the
composite after the matrix metal flowed out. 相似文献
72.
Sanae Shimizu Kazuhiko Yamamoto Caihau Wang Yutaka Satoh Hideki Tanahashi Yoshinori Niwa 《Electrical Engineering in Japan》2005,152(3):29-38
Moving object detection with a mobile image sensor is an important task in robotics and computer vision, when considering the practical use of robotics in human environments. In this paper, we propose a robust method that detects moving objects in the environment using the omnidirectional depth information obtained by a mobile Stereo Omnidirectional System (SOS). In order to detect only the moving objects within the depth image that are obtained by a sensor in motion, we first estimate the ego‐motion of the sensor, and generate a predicted depth image for the current time from the depth obtained at the previous time by only considering the ego‐motion of the sensor. Then the predicted depth image is compared with the actual one obtained at the current time, and the inconsistent regions are detected as moving objects. When the sensor moves, occlusions will occur in the scene and they will cause false detections. However, these false detections can be suppressed by estimating the occlusion regions using the ego‐motion parameters of the sensor and the jump edges in the depth image. The effectiveness of the method is shown with experimental results for a real environment. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 29–38, 2005; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20155 相似文献
73.
Masahiko Hirao Hidekazu Fukuoka Yoshinori Murakami 《Research in Nondestructive Evaluation》1992,4(3):127-138
A computer-driven, swept-frequency measurement technique is developed on the basis of resonance birefringence acoustoelasticity to evaluate the stresses in thin plates. The resonance frequency depends on the thickness and the elastic wave velocity; they change with stress because of the Poisson effect and the acoustoelastic effect. The resonance frequency is obtained from the spectral response curve in the electric impedance of the piezoelectric transducer. The frequency displacement induced by acoustically coupling the transducer can be minimized by employing the resonance peak closest to the transducer fundamental frequency. To illustrate the method, the residual stress is measured in butt-welded aluminum alloy plates and is compared with the results of conventional methods. 相似文献
74.
Shigeaki Abe Yoshinori Nagoya Fumio Watari Hiroto Tachikawa 《Computational Materials Science》2011,50(9):2640-2643
The evaporation processes of water molecules adsorbed in the edge region of graphene have been investigated by means of direct MO–MD method. A large system composed of 29 water molecules and a graphene sheet (C96H24) was used as a model system. The edge carbon atom of graphene was terminated by hydrogen atom. The geometry optimization showed that the water molecules interact with the hydrogen atoms in the edge region of graphene. At low temperature (300 K), the water molecules were dissociated as water clusters from the graphene. On the other hand, in addition to the dissociation of water clusters, the isolated water molecule was also found as dissociation product at high temperature (500 K). The mechanism of water evaporation was discussed on the basis of theoretical results. 相似文献
75.
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
76.
Masaaki Suzuki Yves Maniette Yoshinori Nakata Takeshi Okutani 《Ceramics International》1993,19(6):407-413
The synthesis conditions of SiC ultrafine particles from SiH4 and C2H4 using a CO2 laser were studied and a comparison was made between SiH4---C2H4 and SiH2Cl2---C2H4 systems. Ultrafine SiC particles were synthesized by irradiating a SiH4 and C2H4 gas mixture with a CO2 laser at atmospheric pressure. SiC particles were obtained at a laser power of more than 0·92 kW/cm2.
The behavior of the reaction flame temperature and the extent of the laser light absorption by SiH4---C2H4 was different from that of SiH2Cl2---C2H4, although an abrupt temperature increase was observed in both cases. In the case of SiH4---C2H4 an abrupt increase in the laser light absorption was not observed, whilst it was observed in the case of SiH2Cl2---C2H4. This difference resulted from the difference in liability to form solid carbon particles. 相似文献
77.
Yoshinori Dobashi Kazufumi Kaneda Hideki Nakatani Hideo Yamashita Tomoyuki Nishita 《Computer Graphics Forum》1995,14(3):229-240
When designing interior lighting effects, it is desirable to compare a variety of lighting designs involving different lighting devices and directions of light. It is, however, time-consuming to generate images with many different lighting parameters, taking interreflection into account, because all luminances must be calculated and recalculated. This makes it difficult to design lighting effects interactively. To address this problem, this paper proposes a method of quickly generating images of a given scene illustrating an interreflective environment illuminated by sources with arbitrary luminous intensity distributions. In the proposed method, the luminous intensity ditribution is expressed with basis functions. The proposed method uses a series of spherical harmonic functions as basis functions, and calculates in advance each intensity on surfaces lit by the light sources whose luminous intensity distribution are the same as the spherical harmonic functions. The proposed method makes it possible to generate images so quickly that we can change the luminous intensity distribution interactively. Combining the proposed method with an interactive walk-through that employs intensity mapping, an interactive system for lighting design is implemented. The usefulness of the proposed method is demonstrated by its application to interactive lighting design, where many images are generated by altering lighting devices and/or direction of light. 相似文献
78.
Hiroyuki Mori Yoshinori Sakatani Tatsurou Fujino Kazuyuki Numa 《Electrical Engineering in Japan》2006,156(2):43-51
In this paper, a new efficient feature extraction method is proposed to handle the one‐step‐ahead daily maximum load forecasting. In recent years, power systems become more complicated under the deregulated and competitive environment. As a result, it is not easy to understand the cause and effect of short‐term load forecasting with a bunch of data. This paper analyzes load data from the standpoint of data mining. By it we mean a technique that finds out rules or knowledge through large database. As a data mining method for load forecasting, this paper focuses on the regression tree that handles continuous variables and expresses a knowledge rule as if‐then rules. Investigating the variable importance of the regression tree gives information on the transition of the load forecasting models. This paper proposes a feature extraction method for examining the variable importance. The proposed method allows to classify the transition of the variable importance through actual data. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(2): 43–51, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20104 相似文献
79.
Tomoyuki Nishita Hiroshi Iwasaki Yoshinori Dobashi Eihachiro Nakamae 《Computer Graphics Forum》1997,16(3):C357-C364
The display of natural scenes such as mountains, trees, the earth as viewed from space, the sea, and waves have been attempted. Here a method to realistically display snow is proposed. In order to achieve this, two important elements have to be considered, namely the shape and shading model of snow, based on the physical phenomenon. In this paper, a method for displaying snow fallen onto objects, including curved surfaces and snow scattered by objects, such as skis, is proposed. Snow should be treated as particles with a density distribution since it consists of water particles, ice particles, and air molecules. In order to express the material property of snow, the phase functions of the particles must be taken into account, and it is well-known that the color of snow is white because of the multiple scattering of light. This paper describes a calculation method for light scattering due to snow particles taking into account both multiple scattering and sky light, and the modeling of snow. 相似文献
80.
Nanoscale molecular cavity in crystalline polymer membranes studied by molecular dynamics simulation
The size, shape, and connectivity of cavities in the crystals of syndiotactic polystyrene were investigated by molecular dynamics simulation. Cluster analysis of the free volume in the crystals clearly reveals the cavity structures: large individual holes are in an orderly manner connected by narrow channels. We call such a cavity structure a ‘molecular cavity’. The diffusion behavior and solubility of gases in the molecular cavity were also simulated. The extremely high solubility of a larger gas and the controllable diffusion path in the narrow channels proved the applicability of the concept of the molecular cavity to high performance separation membranes. 相似文献