全文获取类型
收费全文 | 3032篇 |
免费 | 201篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 47篇 |
综合类 | 16篇 |
化学工业 | 692篇 |
金属工艺 | 88篇 |
机械仪表 | 74篇 |
建筑科学 | 271篇 |
矿业工程 | 24篇 |
能源动力 | 90篇 |
轻工业 | 162篇 |
水利工程 | 28篇 |
石油天然气 | 2篇 |
无线电 | 236篇 |
一般工业技术 | 671篇 |
冶金工业 | 134篇 |
原子能技术 | 11篇 |
自动化技术 | 694篇 |
出版年
2024年 | 5篇 |
2023年 | 66篇 |
2022年 | 90篇 |
2021年 | 118篇 |
2020年 | 106篇 |
2019年 | 105篇 |
2018年 | 121篇 |
2017年 | 100篇 |
2016年 | 148篇 |
2015年 | 134篇 |
2014年 | 155篇 |
2013年 | 221篇 |
2012年 | 237篇 |
2011年 | 269篇 |
2010年 | 173篇 |
2009年 | 164篇 |
2008年 | 162篇 |
2007年 | 164篇 |
2006年 | 98篇 |
2005年 | 85篇 |
2004年 | 77篇 |
2003年 | 52篇 |
2002年 | 65篇 |
2001年 | 28篇 |
2000年 | 26篇 |
1999年 | 30篇 |
1998年 | 32篇 |
1997年 | 32篇 |
1996年 | 22篇 |
1995年 | 19篇 |
1994年 | 14篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1972年 | 2篇 |
1961年 | 2篇 |
排序方式: 共有3240条查询结果,搜索用时 15 毫秒
81.
Flexible matrix composites (FMCs) consist of low modulus elastomers such as polyurethanes which are reinforced with high-stiffness continuous fibers such as carbon. This fiber–resin system is more compliant compared to typical rigid matrix composites and hence allows for higher design flexibility. Continuous, single-piece FMC driveshafts can be used for helicopter applications. In the present investigation, an optimization tool using a genetic algorithm approach is developed to determine the best combination of stacking sequence, number of plies and number of in-span bearings for a minimum-weight, spinning, misaligned FMC helicopter driveshaft. In order to gain more insight into designing driveshafts, various loading scenarios are analyzed and the effect of misalignment of the shaft is investigated. This is the first time that a self-heating analysis of a driveshaft with frequency- and temperature-dependent material properties is incorporated within a design optimization model. 相似文献
82.
Reinvestigation of the Lewis acid catalyzed rearrangement of some open-chain permethyloligosilanes with the Al(Fe)Cl(3) catalyst system exhibited several cases of additional reactivity: namely, a fragmentation/cyclization reaction. Introduction of (trimethylsilyl)methyl substituents into the oligosilane substrates strongly facilitated this reaction, yielding cyclic or bicyclic carbacyclosilanes. Investigations concerning the composition of the catalyst system indicated that the incorporation of about 0.1% FeCl(3) into the AlCl(3) lattice provided an effective catalyst. 相似文献
83.
Barry Haseltine Tor‐Ulf Weck Lars Meyer Rob van der Pluijm Oliver Dupont Christoph Alfes Wolfram Jaeger John Roberts Jonathan Silver Dirk Martens O. Pfeffermann Bastian Drewes Erhard Gunkler Jan Kubica Nebojsa Mojsilovic Erhard Gunkler Johann Marx Armin Ohler Hipolito Sousa Rui Sousa Romeu S. Vicente J. R. Mendes Silva Roberto Capozucca 《Mauerwerk》2011,15(6):348-361
84.
85.
Microalloyed steels for forging applications have been newly developed in order to increase strength and toughness properties which thereby give the possibility for light weight constructions.The properties of these steels are set up by a controlled cooling directly from the forging heat without an additional heat treatment.This aim can be achieved on the one hand by a further development of precipitation hardening ferritic pearlitic steels (AFP-steel) due to an extended use of microalloying elements (AFP-M steel) and on the other hand by microalloyed steels which employ a bainitic microstructure (HDB steel).To adjust the targeted microstructure the temperature control has to be assured down to approx.500℃ for the AFP-M steels and down to approx.300℃ for the HDB steels. 相似文献
86.
Three-dimensional chemo-thermomechanically coupled simulation of curing adhesives including viscoplasticity and chemical shrinkage 总被引:1,自引:1,他引:0
Christoph Liebl Michael Johlitz Bülent Yagimli Alexander Lion 《Computational Mechanics》2012,49(5):603-615
Based on the one-dimensional material model developed by Liebl et al. (Arch Appl Mech, 2011) a three-dimensional viscoelastic-viscoplastic material model for small deformations of curing adhesives on the basis of continuum mechanics is proposed in this contribution. The model describes the most relevant phenomena which occur during curing processes in the automotive industry and includes the effects of temperature and degree of cure on the mechanical properties of the material. Thermal expansion as well as chemical shrinkage are also contained. The yield stress for the viscoplastic part of the model goes back to the work of Schlimmer and Mahnken (Int J Numer Meth Eng 63:1461–1477, 2005), but is formulated in reference to the degree of cure and the temperature. Therefore this model considers chemo-thermomechanical coupling and extends the plasticity approach of Schlimmer and Mahnken, which is devised for cured adhesives, to the whole curing range, from the uncured to the fully cured adhesive. A peculiar focus is hereby laid on epoxy resins used in the automotive industry as structural adhesives. 相似文献
87.
88.
89.
90.
Akshay V. Joshi Christoph Dettke Joseph Steingraeber 《Journal of Coatings Technology and Research》2016,13(2):375-383
Gravure is a high throughput printing process, normally associated with speed, quality, and long print runs. It is widely used for printing on shrink films and other substrates. The shrink films, in particular, polyvinyl chloride (PVC) and glycol-modified polyethylene terephthalate (PET-G), are two dominant substrates widely consumed and printed by gravure process. The PVC and PET-G offer different properties which greatly influence the printability. The surface energy of the substrate determines the adhesion and wettability of ink, while electrical properties such as surface and volume resistivity impact electrostatic assist (ESA) performance. The introduction of ESA in gravure further improved the print quality by eliminating dot skips with reduced impression pressure. However, print defects such as print mottle is inevitable. Print mottle occurs due to a discrepancy between substrate, ink, and process parameters which degrade the print quality. These complexities need to be addressed to deliver higher productivity with less print waste. Therefore, the study investigates the effect of process parameters, i.e., substrate type, line screen, air gap (distance between charge bar and impression roller), viscosity, voltage, and speed, and aims to quantify their effect numerically on defect minimization. The Design of Experiments (DOE) was generated for the above-mentioned parameters and analyzed to extract the best combination of process parameters. The optimized setting showed a reduction in solid mottle by 54% and 57% for PET-G and PVC, respectively. 相似文献