全文获取类型
收费全文 | 2329篇 |
免费 | 67篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 112篇 |
综合类 | 3篇 |
化学工业 | 592篇 |
金属工艺 | 68篇 |
机械仪表 | 59篇 |
建筑科学 | 52篇 |
矿业工程 | 1篇 |
能源动力 | 120篇 |
轻工业 | 228篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 204篇 |
一般工业技术 | 383篇 |
冶金工业 | 338篇 |
原子能技术 | 37篇 |
自动化技术 | 201篇 |
出版年
2023年 | 10篇 |
2022年 | 29篇 |
2021年 | 37篇 |
2020年 | 21篇 |
2019年 | 24篇 |
2018年 | 46篇 |
2017年 | 35篇 |
2016年 | 64篇 |
2015年 | 29篇 |
2014年 | 59篇 |
2013年 | 97篇 |
2012年 | 108篇 |
2011年 | 126篇 |
2010年 | 108篇 |
2009年 | 114篇 |
2008年 | 121篇 |
2007年 | 107篇 |
2006年 | 96篇 |
2005年 | 91篇 |
2004年 | 64篇 |
2003年 | 67篇 |
2002年 | 56篇 |
2001年 | 48篇 |
2000年 | 41篇 |
1999年 | 64篇 |
1998年 | 144篇 |
1997年 | 103篇 |
1996年 | 57篇 |
1995年 | 50篇 |
1994年 | 44篇 |
1993年 | 37篇 |
1992年 | 23篇 |
1991年 | 26篇 |
1990年 | 23篇 |
1989年 | 27篇 |
1988年 | 21篇 |
1987年 | 13篇 |
1986年 | 19篇 |
1985年 | 14篇 |
1984年 | 13篇 |
1983年 | 14篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1980年 | 8篇 |
1977年 | 12篇 |
1976年 | 19篇 |
1973年 | 7篇 |
1969年 | 5篇 |
1968年 | 6篇 |
1967年 | 9篇 |
排序方式: 共有2404条查询结果,搜索用时 15 毫秒
51.
A suitable alloying design for improving the punchability of nonoriented electrical steels containing 0.1 % Si was investigated.
The appropriate addition of sulfur to steels containing relatively high manganese content is very useful in obtaining good
punchability without detrimental effects on magnetic properties. 相似文献
52.
Satoshi Ueki Tetsuya Mouri Takahiro Endo Haruhisa Kawasaki 《Artificial Life and Robotics》2016,21(1):31-36
This paper proposes a method for visualizing the stiffness of a soft object in a palpation-support information system by the teleoperation of a robot hand. It is important that a palpation system display a body’s shape and stiffness. In our method, the stiffness of the contact area between the soft object and the robot finger is estimated by a recursive least-squares method with forgetting factor that uses an impedance dynamics model. With the estimated stiffness and direction of contact force, we calculate the scalar parameter for visualization of stiffness. Moreover, we propose a safety control method for the palpation system, which is part of a tele-control method based on will-consensus building. The system configuration, estimated algorithm, and experimental results are presented. 相似文献
53.
Tetsuya Takahashi Yoshinori Dobashi Issei Fujishiro Tomoyuki Nishita Ming C. Lin 《Computer Graphics Forum》2015,34(2):493-502
We propose a stable and efficient particle‐based method for simulating highly viscous fluids that can generate coiling and buckling phenomena and handle variable viscosity. In contrast to previous methods that use explicit integration, our method uses an implicit formulation to improve the robustness of viscosity integration, therefore enabling use of larger time steps and higher viscosities. We use Smoothed Particle Hydrodynamics to solve the full form of viscosity, constructing a sparse linear system with a symmetric positive definite matrix, while exploiting the variational principle that automatically enforces the boundary condition on free surfaces. We also propose a new method for extracting coefficients of the matrix contributed by second‐ring neighbor particles to efficiently solve the linear system using a conjugate gradient solver. Several examples demonstrate the robustness and efficiency of our implicit formulation over previous methods and illustrate the versatility of our method. 相似文献
54.
Akihiro Nagase Eiji Niikura Masaru Shinozaki Tetsuya Nagayasu Taiji Kondo Gosuke Ohashi 《Journal of the Society for Information Display》2013,21(7):295-304
The color gamut is one of the critical parameters that dictate the image quality of displays. The liquid crystal displays using white color light‐emitting diodes (LEDs) as the backlight, though having been widely employed recently, are not very satisfactory in terms of their color gamut because of the broad spectrum inherent to white LEDs. This prompted the authors to develop improved liquid crystal displays using an edge‐lit wide color gamut backlight that used red laser diodes and cyan LEDs. Generating laser beams with high color purity, the laser diodes are light sources with a significant effect on expanding the color gamut. However, laser diodes, red ones in particular, have unfavorable thermal characteristics. To cope with this shortcoming, the authors clearly defined the restrictive criteria for laying out two kinds of light source on the edge‐lit backlight and made a prototype 55‐type laser backlight for performance evaluation. 相似文献
55.
Ryoichi Kawahara Tetsuya Takine Tatsuya Mori Noriaki Kamiyama Keisuke Ishibashi 《Computer Networks》2013,57(6):1560-1576
We consider the mean–variance relationship of the number of flows in traffic aggregation, where flows are divided into several groups randomly, based on a predefined flow aggregation index, such as source IP address. We first derive a quadratic relationship between the mean and the variance of the number of flows belonging to a randomly chosen traffic aggregation group. Note here that the result is applicable to sampled flows obtained through packet sampling. We then show that our analytically derived mean–variance relationship fits well those in actual packet trace data sets. Next, we present two applications of the mean–variance relationship to traffic management. One is an application to detecting network anomalies through monitoring a time series of traffic. Using the mean–variance relationship, we determine the traffic aggregation level in traffic monitoring so that it meets two predefined requirements on false positive and false negative ratios simultaneously. The other is an application to load balancing among network equipments that require per-flow management. We utilize the mean–variance relationship for estimating the processing capability required in each network equipment. 相似文献
56.
Naoki Sakamoto Mitsuru Higashimori Toshio Tsuji Makoto Kaneko 《Intelligent Service Robotics》2009,2(1):53-60
This paper discusses an optimum design approach on robotic food handling by considering the characteristics of viscoelasticity
of object. We pick up a traditional Japanese food, “Norimaki” as a typical example with the viscoelastic characteristics.
We first show that the dynamic characteristics of Norimaki can be expressed by utilizing the Burger model. After testing the
parameter sensitivity, we show an example of the optimum design for determining the combination of the hand stiffness and
the operating velocity. We further show that the resultant plastic deformation can be formulated with the exact solution. 相似文献
57.
Kaneko K Inoke K Sato K Kitawaki K Higashida H Arslan I Midgley PA 《Ultramicroscopy》2008,108(3):210-220
The growth mechanism and morphology of Ge precipitates in an Al-Ge alloy was characterized by a combination of in-situ transmission electron microscopy, high-resolution transmission electron microscopy and three-dimensional electron tomography. Anisotropic growth of rod-shaped Ge precipitates was observed by in-situ transmission electron microscopy over different time periods, and faceting of the precipitates was clearly seen using high-resolution transmission electron microscopy and three-dimensional electron tomography. This anisotropic growth of rod-shaped Ge precipitates was enhanced by vacancy concentration as proposed previously, but also by surface diffusion as observed during the in-situ experiment. Furthermore, a variety of precipitate morphologies was identified by three-dimensional electron tomography. 相似文献
58.
Particulate TiC-reinforced aluminum composite specimens were processed by compacting a mixture of titanium, carbon, and aluminum
powders into preforms that were infiltrated with molten aluminum and subsequently heated in a differential thermal analyzer
to about 1573 K under argon atmosphere. The onset of formation of TiC particles began at about 1150 K by reaction of TiAl3 with Al4C3. Subsequent formation of TiC particles at higher temperatures to approx-imately 1265 K occurred by direct reaction of carbon
with TiAl3. Above this temperature, the TiC particles coarsened with increasing temperature from an initial size of about 0.15μm. TiC
particles were also produced in preforms that were not infiltrated; however, the presence of liquid aluminum in infiltrated
specimens inhibited particle agglomeration and sintering. Infil-trated preforms could, therefore, serve as excellent "master
alloys" for subsequent dilution in an aluminum melt and processing of metal-matrix composites (MMCs) reinforced with sub-micron
TiC particulates.
Formerly Research Scientist, Massachusetts Institute of Technology, Cambridge, MA 02139 相似文献
59.
Hideyuki Nakano Hiroyuki Tetsuka Michelle J. S. Spencer Tetsuya Morishita 《Science and Technology of Advanced Materials》2018,19(1):76-100
Mono-elemental two-dimensional (2D) crystals (graphene, silicene, germanene, stanene, and so on), termed 2D-Xenes, have been brought to the forefront of scientific research. The stability and electronic properties of 2D-Xenes are main challenges in developing practical devices. Therefore, in this review, we focus on 2D free-standing group-IV graphene analogs (graphene quantum dots, silicane, and germanane) and the functionalization of these sheets with organic moieties, which could be handled under ambient conditions. We highlight the present results and future opportunities, functions and applications, and novel device concepts. 相似文献
60.
Chung Loong Yiin Suzana Yusup Armando T. Quitain Yoshimitsu Uemura Mitsuru Sasaki Tetsuya Kida 《Clean Technologies and Environmental Policy》2018,20(9):1987-2000
Recently, the development of efficient and environmentally benign solvents has received great attention to replace current harsh organic solvents. In this context, low-transition-temperature mixtures (LTTMs) have emerged as favorable green solvents for biomass delignification. Palm oil biomass, empty fruit bunch (EFB) was pretreated with commercial l-malic acid and microwave hydrothermally extracted cactus malic acid-derived LTTMs at 60, 80, and 100 °C. The LTTMs applied in this study were derived from malic acid–choline chloride–water and malic acid–monosodium glutamate–water with a molar ratio of 2:4:2 and 3:1:5, respectively. Three first-order reactions were used to express the delignification kinetic model of EFB. The first term was based on the initial stage and assigned as infinite due to the fast rate of delignification which could not be detected. The second and third terms were proportional to bulk and residual delignification stages. A good agreement was obtained between the kinetic model and the experimental data obtained in this study with R2?≥?0.91. The activation energies for the delignification reactions using l-malic acid and cactus malic acid-based LTTMs in the bulk and residual stages were approximated as 36–56 and 19–26 kJ/mol and 34–90 and 47–87 kJ/mol, respectively. 相似文献