全文获取类型
收费全文 | 242篇 |
免费 | 7篇 |
国内免费 | 8篇 |
专业分类
化学工业 | 55篇 |
金属工艺 | 10篇 |
机械仪表 | 5篇 |
建筑科学 | 4篇 |
能源动力 | 8篇 |
轻工业 | 13篇 |
石油天然气 | 2篇 |
无线电 | 12篇 |
一般工业技术 | 32篇 |
冶金工业 | 93篇 |
自动化技术 | 23篇 |
出版年
2021年 | 2篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 8篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 10篇 |
2006年 | 5篇 |
2005年 | 9篇 |
2004年 | 4篇 |
2003年 | 13篇 |
2002年 | 4篇 |
2001年 | 10篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 3篇 |
1995年 | 9篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 3篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1966年 | 3篇 |
1935年 | 2篇 |
排序方式: 共有257条查询结果,搜索用时 21 毫秒
31.
Wlodzimierz Gawronski 《Computers & Structures》1976,6(1):17-27
Input data in the computation of free motion (the inertia and stiffness matrices) contain some errors. These errors generate errors of output data (the natural frequency vector, the natural mode vectors). In this paper the relationships between errors of input and output data in the computation of free motion are derived. This analysis is applied to the finite element method. The paper presents program ERROR, which computes the errors of the natural frequencies created by the inertia matrix errors. An example of the influence of the errors of the mass and of the mass moment of inertia on the natural frequencies of a ship hull is presented. 相似文献
32.
33.
To improve materials performance like the temperature of deformation under flexural load of thermoplastic polyurethanes (TPU) blending with thermoplastics is sensible. A good compatibilization and phase adhesion of thermodynamical incompatible blend-components can be achieved by the use of the right coupling agents. In the case of blends with TPU and PA6 diisocyanate is given into the melt during the extrusion. Through the chemical reactions effects of compatibilization are achieved in the cases of blends with polyesterpolyurethanes and PA6 produced by extrusion and injection moulding and by reactions in solution, too. These could be perceived as consequence of MDI-initiated reactions within the phase boundary layer. The possible reactions with the PA6-phase will be discussed by the use of a model-system made in solution. No effects of compatibilization by MDI could be proved in the polyetherpolyurethan/PA6-system. The chemical characterization of the blends was realized by GPC and FTIR whereas the properties of the morphology are proved with the help of DSC, DMA and transmission electron microscopy (TEM). 相似文献
34.
Plug-type, ZrO2-based oxygen sensors have been used for long-term measurements of oxygen activity in Fe–O–Cr and Ni–O–Cr melts. In these melts, equilibrated with chromium oxide, oxygen activities aO were determined as a function of Cr content. From the experimental results, data were derived for activity coefficients fO and of 1st and 2nd order interaction parameters eOCr and rOCr. Cr2O3 has been identified as the oxide phase in equilibrium with the metal melt at ≥ 5 wt.% Cr in the case of iron and at ≥ 0.2 wt.% Cr in the case of nickel. Oxygen activities and oxygen contents in Cr-containing iron melts are lowered with increasing additions of nickel. Further investigations were directed to aO determination in Fe–O–Cr–C and Fe–O–Cr–Al melts. 相似文献
35.
Hsiao-Wei Wen Wlodzimierz Borejsza-Wysocki Thomas R. DeCory Antje J. Baeumner Richard A. Durst 《European Food Research and Technology》2005,221(3-4):564-569
In this study, conditions for extracting the major peanut allergen (Ara h1) from chocolate were optimized, and the extracted samples were analyzed by a lateral flow assay (LFA) using liposomal nanovesicles. The optimal conditions using peanut-spiked chocolate were found to be extraction with a mixture of phosphate buffered saline and hexane for 30 min at 35 °C. After centrifugation, the buffer portion was treated with insoluble poly(vinylpolypyrrolidone) to remove phenolic compounds, and then analyzed by the LFA. The entire analysis, including sample preparation and LFA, could be easily completed within 2 h, and the detection limit was 158 g of peanuts/g of chocolate. 相似文献
36.
It has not been possible previously to do a complete study of drawn polyolefins using SANS techniques because of void scattering. In the case of polypropylene this can be reduced sufficiently to permit measurements with the Q-vector perpendicular and parallel to the draw direction. A complete analysis has been carried out with a draw ratio 8:1 in which the PPD molecules of narrow molecular weight distribution and molecular weights in the range 390 000 to 50 000 are molecularly dispersed in a drawable PPH matrix. The dimensional changes on drawing are to extend the molecule by a factor of 2 with a corresponding reduction in diameter to a maximum of 40%. We have interpreted the data at high Q on the basis that the molecule is not uniformly distributed but the majority is folded into sub-units and the number of these is proportional to the molecular weight of the polymer. A further feature of the sub-units structure is that its length is approximately two lamellae thick, this dimension is similar to the SANS scattering length (In) identified in the study of isotropic material. The double stems belonging to the same molecule have been concentrated by the drawing process some 16 times and a consequence of this is to markedly change the Kratky curves from the isotropic case. Notwithstanding, this increase in the packing of the molecule, the stems are still, on average, some 40 Å apart and surrounded by many stems belonging to other macromolecules. Similarly, each sub-unit is surrounded by sub-units belonging to neighbouring molecules. 相似文献
37.
Messungen des elektrischen Widerstandes an gesinterten und schmelzflüssigen Kalk-Phosphorsäure-Proben bei Kalkgehalten von 33,9 bis 100% und Temperaturen von 1000 bis 1650 °C. Berechnung der spezifischen elektrischen Leitfähigkeiten mit Hilfe von Zellkonstanten, die an wäßrigen Eichlösungen bekannter Leitfähigkeit ermittelt wurden. Darstellung der Leitfähigkeitsisothermen im Zustandsschaubild Kalk-Phosphorsäure. 相似文献
38.
D.G.H. Ballard A.N. Burgess P. Cheshire E.W. Janke A. Nevin J. Schelten 《Polymer》1981,22(10):1353-1354
Experiments have been performed on deuterated polycarbonate chains with five different molecular weights, randomly dispersed in a protonated polycarbonate matrix. There is evidence for some ester interchange in the melt. This requires that the values of Mw obtained from the SANS data be used. The measured radii of gyration were found to follow the relationship: Rw = βMaw, with β = 0.457(9) and α = 0.5. The high value for β compared with that for polystyrene (β = 0.27) is a reflection of the stiffer backbone in polycarbonate. 相似文献
39.
40.
Fluorescent Diarylethene Photoswitches—A Universal Tool for Super‐Resolution Microscopy in Nanostructured Materials
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Oleksii Nevskyi Dmytro Sysoiev Jes Dreier Simon Christoph Stein Alex Oppermann Florian Lemken Tobias Janke Jörg Enderlein Ilaria Testa Thomas Huhn Dominik Wöll 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(10)
Super‐resolution fluorescence microscopy allows for unprecedented in situ visualization of biological structures, but its application to materials science has so far been comparatively limited. One of the main reasons is the lack of powerful dyes that allow for labeling and photoswitching in materials science systems. In this study it is shown that appropriate substitution of diarylethenes bearing a fluorescent closed and dark open form paves the way for imaging nanostructured materials with three of the most popular super‐resolution fluorescence microscopy methods that are based on different concepts to achieve imaging beyond the diffraction limit of light. The key to obtain optimal resolution lies in a proper control over the photochemistry of the photoswitches and its adaption to the system to be imaged. It is hoped that the present work will provide researchers with a guide to choose the best photoswitch derivative for super‐resolution microscopy in materials science, just like the correct choice of a Swiss Army Knife's tool is essential to fulfill a given task. 相似文献