全文获取类型
收费全文 | 694篇 |
免费 | 35篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 28篇 |
综合类 | 2篇 |
化学工业 | 258篇 |
金属工艺 | 9篇 |
机械仪表 | 10篇 |
建筑科学 | 30篇 |
矿业工程 | 1篇 |
能源动力 | 2篇 |
轻工业 | 87篇 |
无线电 | 36篇 |
一般工业技术 | 97篇 |
冶金工业 | 94篇 |
原子能技术 | 6篇 |
自动化技术 | 72篇 |
出版年
2022年 | 10篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 15篇 |
2015年 | 18篇 |
2014年 | 15篇 |
2013年 | 32篇 |
2012年 | 27篇 |
2011年 | 26篇 |
2010年 | 20篇 |
2009年 | 26篇 |
2008年 | 27篇 |
2007年 | 25篇 |
2006年 | 15篇 |
2005年 | 17篇 |
2004年 | 20篇 |
2003年 | 16篇 |
2002年 | 12篇 |
2001年 | 15篇 |
2000年 | 8篇 |
1999年 | 14篇 |
1998年 | 22篇 |
1997年 | 18篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 12篇 |
1991年 | 8篇 |
1990年 | 11篇 |
1989年 | 16篇 |
1988年 | 13篇 |
1987年 | 19篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 11篇 |
1980年 | 4篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 12篇 |
1975年 | 7篇 |
1974年 | 12篇 |
1973年 | 7篇 |
1971年 | 4篇 |
排序方式: 共有732条查询结果,搜索用时 15 毫秒
61.
Scale-down of chemical engineering pilot plant – what is attainable? The use of fully automated experimental laboratory-scale plantoffer interesting possibilities for assessment of the economic operation and technical feasibility of new or modified processes. An important condition for the success of this kind of experimental approach is the availability of miniaturized equipment, machines, and sensors. The goal of such experimental plant can be both the process engineering development of individual process steps and also integrated running to model complete processes. Moreover, questions of scale-up can be studied and typical quantities can be provided. The state of the art is reported with the aid of selected examples of equipment and mechanical components and measurement and control units. 相似文献
62.
The processing parameters of finish rolling and cooling of three HSLA steels were varied in a wide range applying the plane strain hot compression simulation test on the hot deformation simulator (Wumsi). Evaluating the flow curves of the deformation steps, some metallurgical phenomena in austenite during hot deformation could be determined. The results of material testing after the simulation experiments exhibit a strong correlation between the finish rolling and cooling conditions and the final mechanical properties of the steels tested. As a way to increase strength, lowering finishing temperatures and/or accelerating cooling after finish rolling proved to be most effective. To improve notch toughness, on the other hand, a high total finishing strain should be applied as well as low finishing temperatures, however, above Ar3. 相似文献
63.
We use a two-band k · p Hamiltonian to describe the subband structure in strained silicon thin films. The model describes the dependence of the transversal effective mass on strain and film thickness. However, it is found that the two-band k · p model is unable to describe recently observed large valley splitting. Therefore a generalization of the model is necessary. To go beyond the k · p theory, an auxiliary tight-binding model defined on a lattice of sites containing two localized orbitals is introduced in such a way that it reproduces the bulk dispersion obtained from the two-band k · p model. Corresponding dispersion relations including strain are obtained. We discuss an alternative mechanism to create and control the valley splitting by applying shear strain. The valley splitting increases with increased shear strain and decreasing film thickness and can be larger than the spin splitting. This makes silicon-based quantum devices promising for future applications in quantum computing. 相似文献
64.
Adsorbents are widely‐used in the area of cleaning as well as enrichment of gas components. For the regeneration of clinoptilolite loaded with ammonia, a packed‐bed reactor was developed on the basis of a dielectric barrier discharge. It was proved that adsorbed NH3 is released at relatively low temperature and low energy consumption. For the further optimization of the method the influence of the power and the pulse break ratio of sustaining voltage were tested. It was shown that with the chosen plasma method the absorber material was loaded repeatedly and subsequently regenerated. 相似文献
65.
66.
67.
Optimal control of option portfolios and applications 总被引:1,自引:0,他引:1
68.
69.
70.
Donald E. Wasserman Stephen D. Hudock Jack F. Wasserman Logan Mullinix Steven J. Wurzelbacher Karl V. Siegfried 《人机工程学与制造业中的人性因素》2002,12(2):211-226
Vibration acceleration was triaxially and basicentrically measured, and digital‐audio‐tape‐recorded with each axis separately evaluated using both the ANSI S3.34 and ACGIH hand‐arm vibration (HAV) guidelines, for two pairs of pneumatic handheld grinders commonly used in metal fabrication operations including shipyards. Each tool pair consisted of a new and used grinder of the same model, performing the same simulated grinding tasks using new small grinding wheels, carbide burrs, wire brushes, and flap wheels. The results of this limited study showed, primarily, that the HAV standards were not exceeded, but there was a consistent tendency for the acceleration levels to increase between new and used tools, ranging from 11% to 66% on the Z‐axis, 13% to 66% on the Y‐axis, 44% to 58% on the X‐axis, when tasks involved using grinding wheels and carbide burrs (hard implements). The results were mixed when using disposable wire brushes and flap wheels (softer implements). The overall results suggest the need for and implementation of a regular tool vibration monitoring and maintenance program as a primary element to help maintain tool acceleration levels to a minimum. © 2002 Wiley Periodicals, Inc. 相似文献