全文获取类型
收费全文 | 840篇 |
免费 | 24篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 70篇 |
化学工业 | 319篇 |
金属工艺 | 12篇 |
机械仪表 | 15篇 |
建筑科学 | 21篇 |
矿业工程 | 1篇 |
能源动力 | 33篇 |
轻工业 | 47篇 |
石油天然气 | 1篇 |
无线电 | 36篇 |
一般工业技术 | 174篇 |
冶金工业 | 19篇 |
原子能技术 | 19篇 |
自动化技术 | 99篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 14篇 |
2020年 | 11篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 9篇 |
2015年 | 13篇 |
2014年 | 23篇 |
2013年 | 50篇 |
2012年 | 42篇 |
2011年 | 45篇 |
2010年 | 43篇 |
2009年 | 45篇 |
2008年 | 43篇 |
2007年 | 48篇 |
2006年 | 37篇 |
2005年 | 38篇 |
2004年 | 38篇 |
2003年 | 31篇 |
2002年 | 30篇 |
2001年 | 14篇 |
2000年 | 28篇 |
1999年 | 32篇 |
1998年 | 24篇 |
1997年 | 19篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 13篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有866条查询结果,搜索用时 15 毫秒
81.
To modify the surface of vapor grown carbon fiber (VGCF), poly(ethylene-block-ethylene oxide) (PE-b-PEO, Mn=1400, PEO content=50 wt%) was successfully grafted onto the surface by using γ-ray irradiation of the PE-b-PEO-adsorbed VGCF in solvent-free system. It is found that the percentage of polymer grafting reached 15.0% when the PE-b-PEO-adsorbed VGCF was irradiated by γ-ray over 40 kGy dose at 110 °C, but at the lower irradiation temperature of 75 °C, the grafting reaction scarcely proceeded. This indicates that polymer radicals formed by γ-ray irradiation were successfully trapped by VGCF surface above melting point of PE-b-PEO. On the other hand, when the dispersion of VGCF in THF solution of PE-b-PEO was irradiated, the percentage of PE-b-PEO grafting was less than 4.0%. It was confirmed by a field-emission scanning electron microscope (FE-SEM) that the surface of the VGCF was uniformly covered by grafted PE-b-PEO. In addition, the surface free energy of ungrafted and PE-b-PEO-grafted VGCF was determined. 相似文献
82.
The mechanism of enhanced PVC impact strength of poly(vinyl chloride) modified by an acrylic graft copolymer was studied by the three-point bending test on a U-notched bar. In the mechanism, the void formation from the modifier released the constrained strain. The release suppresses the stress below the fibril strength in the material; consequently, stable deformation can develop over a large area and, thus, the impact strength of PVC modified by the acrylic graft copolymer is improved. © 1996 John Wiley & Sons, Inc. 相似文献
83.
Fast Labelling of Natural Scenes Using Enhanced Knowledge 总被引:1,自引:0,他引:1
Hiroki Hayashi Mineichi Kudo Jun Toyama Masaru Shimbo 《Pattern Analysis & Applications》2001,4(1):20-27
A new technique for labelling natural scenes is proposed. This technique labels disjoint regions on an image of a natural
scene on the basis of knowledge about the relationship among objects. The proposed technique consists of three stages: (1)
segmentation, (2) initial labelling, and (3) label improvement. One of the most promising previous techniques uses simulated
annealing to find the solution, while our technique uses local hill-climbing with enhanced knowledge for speeding up the processing.
Local hill-climbing is known to be easy to be captured by a local minimum. We solved this problem by enhancing the knowledge
being used as constraints for the search. Our knowledge represents 1-to-n relationships among regions, pair-wise relationships of regions, and relative locations of the regions to the image. In addition,
we introduced two region features: an entropy in intensity; and a linearity of contours of each region. The linearity evaluation
aims to distinguish artificial objects from natural objects. The validity of the technique is supported by some experiments.
These experiments showed that the proposed technique is much faster with the almost same accurate. 相似文献
84.
85.
86.
This paper reports the preparation of highly mesoporous carbon membranes, which are obtained by the pyrolysis of sol-gel derived mesoporous polymer membranes using resorcinol and formaldehyde (RF). Two series of RF carbon membranes were prepared by changing the resorcinol to catalyst molar ratio. The nitrogen adsorption-desorption measurement shows that the RF carbon membranes possess a well-developed mesoporous structure with controlled pore diameters of 5.48 nm and 13.9 nm. The helium and nitrogen permeances of both RF carbon membranes were independent of the feed pressure, indicating that there was no contribution of viscous flow and the membranes are initially crack-free. The gas permeation result showed that the dominant mechanism of gas transport through both the RF carbon membranes is Knudsen diffusion. With regard to the permeation of condensable gases such as CH4 and CO2, it was observed that the surface flow also contributes to the total permeation. 相似文献
87.
Sho Kataoka Takuji Yamamoto Yuki Inagi Akira Endo Masaru Nakaiwa Takao Ohmori 《Carbon》2008,46(10):1358-1360
Mesoporous carbon thin films with ordered structures were prepared by using resorcinol-surfactant self-assembly. A mixture of resorcinol, surfactant, and ethanol coated on silicon substrates was exposed to formaldehyde vapor as a cross-linking agent to form structured resorcinol/formaldehyde resin films. The films were then carbonized at 800 °C in an inert atmosphere to remove the surfactant and to obtain structured carbon materials. With this vapor infiltration method, thin films with several structures were obtained from the same precursor solution by employing different vapor infiltration temperatures. The results were interpreted from the transformation of the self-assembly during the vapor infiltration process. 相似文献
88.
Junichi Koseki Hong Kimhor Susumu Nakajima Sarju Mulmi Kenji Watanabe Masaru Tateyama 《Soils and Foundations》2010,50(5):747-755
In order to investigate the seismic behavior of conventional type and geosynthetic-reinforced soil retaining walls, 1-g model shaking tests were conducted. Model walls having a height of about 50 cm were placed on a subsoil layer and backfilled with a layer of dense dry Toyoura sand. They were subjected to several steps of horizontal irregular excitations. As a result, generation of negative pore air pressure in the backfill was observed. The maximum amplitude of the negative pore air pressure during each shaking step increased with the base acceleration. Based on analyses of the measured data, it was inferred that such negative pore air pressure was caused by outward wall displacement relative to the backfill and not by dilative behavior of the backfill. It would cause a reduction in the seismic earth pressures exerted from the backfill. This feature suggests an advantage of a rigid full-height facing for reinforced soil walls over the segmental types of facing. A simplified numerical procedure to evaluate earth pressure was applied while considering the effects of the negative pore air pressure, and it could qualitatively simulate the measured behavior in terms of the seismic earth pressure and the angle of failure plane in the backfill. 相似文献
89.
Naota Torii Atushi Okai Kazuaki Shibuki Taku M. Aida Masaru Watanabe Masayuki Ishihara Hiroichi Tanaka Yoshiyuki Sato R.L. Smith 《Biomass & bioenergy》2010,34(6):844-850
To convert cellulosic organics contained in industrial paper sludge into glucose, reaction of pseudo paper sludge composed of cellulose and inorganic compounds (calcium carbonate (CaCO3), talc (Mg3(Si4O10)(OH)2), kaolin (Al2(Si2O5)(OH)4)) under hydrothermal conditions was studied. Significant amounts of glucose (ca. 23%) could be produced from cellulose in the absence of CaCO3 for reaction in water at 523 K and 12 min reaction time. On the other hand, in the presence of CaCO3, most glucose decomposed over all conditions, whereas the addition of talc and kaolin to the mixtures increased the glucose yield to about 30%. For the case of chemical recycle of paper sludge with hydrothermal treatment to obtain d-glucose, it can be concluded that it is preferable to separate the calcium carbonate from the paper sludge before hydrothermal treatment. 相似文献
90.
Abe Shoma Ogawa Jun Watanabe Yosuke Shiblee MD Nahin Islam Kawakami Masaru Furukawa Hidemitsu 《Artificial Life and Robotics》2023,28(3):609-617
Artificial Life and Robotics - Soft modular robotics combines soft materials and modular mechanisms. We are developing a vacuum-driven actuator module, MORI-A, which combines a 3D-printed flexible... 相似文献