全文获取类型
收费全文 | 212篇 |
免费 | 4篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 66篇 |
金属工艺 | 2篇 |
建筑科学 | 14篇 |
能源动力 | 3篇 |
轻工业 | 12篇 |
无线电 | 3篇 |
一般工业技术 | 52篇 |
冶金工业 | 44篇 |
原子能技术 | 2篇 |
自动化技术 | 17篇 |
出版年
2021年 | 3篇 |
2019年 | 2篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 10篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 8篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 1篇 |
1967年 | 2篇 |
1930年 | 1篇 |
排序方式: 共有216条查询结果,搜索用时 15 毫秒
11.
The initial slope of the time-dependent scattering function and the static structure factor S(q) of macromolecules in good solvents are calculated without using the Gaussian assumption. For S(q), the scaling relation S(q)~q?1.7 is confirmed in the intermediate q range, whereas no q dependent cross-over behaviour can be observed. The calculation of reveals a q3 dependence in this range and no evidence is seen for an exponent apart from 3. The time-dependent scattering function S(q,t) is treated within the framework of the Gaussian assumption. Hydrodynamic as well as excluded volume interactions are incorporated. It has been found that excluded volume effects decrease the decay of the scattering function in comparison with the Gaussian chain. 相似文献
12.
Fan X Moros EG Straube WL 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1999,46(4):830-841
An equivalent concentric-ring ultrasound phased array method was developed to estimate ultrasonic continuous wave fields generated by axisymmetric single-source transducers. The method models a given source as a concentric-ring phased array by mathematically segmenting it into many rings and subsequently finding the amplitude and phase for each ring that produces an acoustic field similar to the field of the single-source transducer. The excitation source of each ring was calculated using an inverse technique based on complex pressure measurements along a radial line close to the source. The predicting abilities of the method are evaluated by comparing measured and estimated ultrasound fields for six different transducers. The results show that the concentric-ring equivalent phased array method (CREPAM) is able to estimate quantitatively the ultrasound fields generated by large axisymmetric planar and focused transducers. 相似文献
13.
14.
15.
16.
Carsten Wegener Michael Peter Kennedy Bernd Straube 《Journal of Electronic Testing》2001,17(5):409-416
By their nature, mixed-signal circuits have to be tested for both structural integrity and parametric performance. For the example of data converters we review test pattern selection strategies geared towards structural and performance testing. We introduce a novel test pattern selection strategy that merges both objectives, and by that we achieve a significant reduction in the size of the set of test patterns applied on the production line. 相似文献
17.
In recent years efforts have been increased to work with more intelligent membranes which render more than normal filtration properties. Thus, membranes have been prepared using chemically modified polymers or have been furnished with additives in order to increase their selectivity and/or special sorbing capabilities. In this paper, methods are described how commercially available polysulfone membranes can be functionalized by chemical reactions without disintegrating their mechanical properties. For this purpose, Sulfonation, chloromethylation, aminomethylation, and lithiation reactions were applied. A broad spectrum for further conversions modified membranes is opened by these chemical reactions which allow an individual fitting of the membranes with special substitutes. The chemical reactions and the analytical procedures are also described. 相似文献
18.
D. V. Lyubimov T. P. Lyubimova A. V. Straube 《Microgravity science and technology》2005,16(1-4):210-214
Accumulation of solid particles suspended in unsteady convective flows is under theoretical investigation. The principal goal is to understand and interpret recent experiments by D. Schwabe [1,2]. Providing that volume particle concentration, nonisothermality, and relative size of particle are small, an effective single-fluid theoretical model is developed. The peculiarity of the obtained model is taking into account the distinction between fluid and particle inertia. This model is further applied to study particle accumulation in different flow setups: in a model oscillatory flow in a canal heated from below and subjected to the modulated gravity and in the Marangoni flow in a half-zone under microgravity conditions. These problems are investigated numerically by means of finite difference technique. We demonstrate, that the developed theoretical model properly describes generic features of particle accumulation in unsteady flows. Particularly, heavy particles tend to leave the centers of vortices, where the flow vorticity is maximal, and accumulate at their periphery. From numerical simulations in a floating zone, we try to clarify particle dynamics in Schwabe’s setup. 相似文献
19.
Peter Hölscher Hans-Joachim Knölker Ekkehard Winterfeldt 《Israel journal of chemistry》1991,31(3):187-194
A simple enantioselective synthesis of (+)epi-elenoic acid is reported and its transformation into (+)-elenoic acid is described. Well-established procedures transform these compounds into the antipodes of tetrahydroalstonine, aricine, and reserpinine. 相似文献
20.
Ekkehard Richter 《化学工程与技术》1990,13(1):101-112
The BF-Uhde-Mitsui Process uses active coke for SO2- and NOx-removal from flue gases in the temperature range between 100 and 190 °C, Experimental methods of thermal regeneration were applied to the evaluation of the state of the adsorbent after use in flue gas cleaning and of the parameters for disrober design. A reaction model was derived from experiments carried out in differential and back-mix reactors. The parameters were evaluated by adaptation of the model to the adsorption spectra. The model was successfully applied to the regeneration of active coke in a fluidized bed reactor. 相似文献