全文获取类型
收费全文 | 447篇 |
免费 | 4篇 |
国内免费 | 1篇 |
学科分类
工业技术 | 452篇 |
出版年
2021年 | 8篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 11篇 |
2013年 | 12篇 |
2012年 | 15篇 |
2011年 | 19篇 |
2010年 | 17篇 |
2009年 | 20篇 |
2008年 | 23篇 |
2007年 | 22篇 |
2006年 | 21篇 |
2005年 | 21篇 |
2004年 | 17篇 |
2003年 | 9篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 13篇 |
1998年 | 20篇 |
1997年 | 15篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1980年 | 12篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有452条查询结果,搜索用时 31 毫秒
41.
Volkmar Lankau Hans-Peter Martin Renate Hempel-Weber Niels Oeschler Alexander Michaelis 《Journal of Electronic Materials》2010,39(9):1809-1813
SiC-B4C composites with various values of SiC-to-B4C ratio and grain size were fabricated by pressureless sintering. This paper presents the results of current investigations
of this composite material. This includes the parameters of manufacture (shrinkage, density, and open porosity), thermoelectric
properties (electrical and thermal conductivity, and thermopower), and material characterization (x-ray diffraction, scanning
electron microscopy, oxidation resistance, and thermal expansion). The results indicate high potential of this composite as
an alternative material for thermoelectric applications at high temperatures. The Seebeck coefficient of the composite was
higher than that of the single-component materials B4C and SiC and reached 400 μV/K at 500°C. 相似文献
42.
The subject of this research is the automated startup procedure of a PI state-controlled rolling-mill motor by using evolutionary algorithms. Compared to the conventional PI speed control, applying the method of deliberate pole placement to the state controller design succeeds in improving the transient response of setpoint and disturbance changes. To put the PI state-controlled drive with observer into operation to obtain a controller with a high robustness and dynamics, the precise knowledge of this physical parameter is necessary. An evolution-based system is used to solve the estimation problem. A high degree of reliability respecting multimodal characteristics and robustness against random noise is expected from the identification method. Evolutionary algorithms fulfill this requirement. With genetic operators like mutation, crossover, and selection, evolutionary algorithms mimic the principles of organic evolution in order to solve the optimization problem 相似文献
43.
Taking up the common challenges in biocatalysis, a group of industrialists decided to react with a bottom-up solution, and created the Swiss Industrial Biocatalysis Consortium (SIBC). The Swiss Industrial Biocatalysis Consortium is a pre-competitive working group to better implement and utilize existing know-how and resources in biocatalysis, and to influence and shape the economic and educational political environment. Recent examples of activities are outlined. 相似文献
44.
Hans-Peter Hoenes 《电子设计应用》2010,8(2)
本文在对现代汽车电子行业重要元件IGBT的故障机制进行分析的基础上,提出了一种可确保超越AEC Q100/101汽车质量认证标准的可靠性设计方案,并对其流程和独特性进行了详细的说明. 相似文献
45.
Karin Pichler Stefan Fischerauer Peter Ferlic Elisabeth Martinelli Hans-Peter Brezinsek Peter J. Uggowitzer Jörg F. Löffler Annelie-Martina Weinberg 《JOM Journal of the Minerals, Metals and Materials Society》2014,66(4):573-579
The use of biodegradable magnesium implants in pediatric trauma surgery would render surgical interventions for implant removal after tissue healing unnecessary, thereby preventing stress to the children and reducing therapy costs. In this study, we report on the immunological response to biodegradable magnesium implants—as an important aspect in evaluating biocompatibility—tested in a growing rat model. The focus of this study was to investigate the response of the innate immune system to either fast or slow degrading magnesium pins, which were implanted into the femoral bones of 5-week-old rats. The main alloying element of the fast-degrading alloy (ZX50) was Zn, while it was Y in the slow-degrading implant (WZ21). Our results demonstrate that degrading magnesium implants beneficially influence the immune system, especially in the first postoperative weeks but also during tissue healing and early bone remodeling. However, rodents with WZ21 pins showed a slightly decreased phagocytic ability during bone remodeling when the degradation rate reached its maximum. This may be due to the high release rate of the rare earth-element yttrium, which is potentially toxic. From our results we conclude that magnesium implants have a beneficial effect on the innate immune system but that there are some concerns regarding the use of yttrium-alloyed magnesium implants, especially in pediatric patients. 相似文献
46.
47.
Hans-Peter Seidel 《Computer Aided Geometric Design》1991,8(6):439-441
Polar forms are used to find the B-spline control points for Hermite interpolation. 相似文献
48.
49.
J Behlke K Heidrich M Naumann EC Müller A Otto R Reuter T Kriegel 《Canadian Metallurgical Quarterly》1998,37(34):11989-11995
Homodimeric hexokinase 2 from Saccharomyces cerevisiae is known to have two sites of phosphorylation: for serine-14 the modification in vivo increases with glucose exhaustion [Kriegel et al. (1994) Biochemistry 33, 148-152], while for serine-157 it occurs in vitro with ATP in the presence of nonphosphorylateable five-carbon analogues of glucose [Heidrich et al. (1997) Biochemistry 36, 1960-1964]. We show now by site-directed mutagenesis and sedimentation analysis that serine-14 phosphorylation affects the oligomeric state of hexokinase, its substitution by glutamate causing complete dissociation; glutamate exchange for serine-157 does not. Phosphorylation of wild-type hexokinase at serine-14 likewise causes dissociation in vitro. In view of the higher glucose affinity of monomeric hexokinase and the high hexokinase concentration in yeast [Womack, F., and Colowick, S. P. (1978) Arch. Biochem. Biophys. 191, 742-747; Mayes, E. L., Hoggett, J. G., and Kellett, G. L. (1983) Eur. J. Biochem. 133, 127-134], we speculate that the in vivo phosphorylation at serine-14 as transiently occurring in glucose derepression might provide a mechanism to improve glucose utilization from low level and/or that nuclear localization of the monomer might be involved in the signal transduction whereby glucose causes catabolite repression. 相似文献
50.