全文获取类型
收费全文 | 196篇 |
免费 | 4篇 |
专业分类
电工技术 | 13篇 |
化学工业 | 55篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
建筑科学 | 12篇 |
轻工业 | 9篇 |
水利工程 | 3篇 |
无线电 | 8篇 |
一般工业技术 | 52篇 |
冶金工业 | 30篇 |
原子能技术 | 1篇 |
自动化技术 | 15篇 |
出版年
2021年 | 2篇 |
2018年 | 2篇 |
2016年 | 8篇 |
2015年 | 3篇 |
2014年 | 12篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 8篇 |
2007年 | 2篇 |
2005年 | 2篇 |
2004年 | 6篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1971年 | 2篇 |
1967年 | 4篇 |
1966年 | 2篇 |
1929年 | 1篇 |
1928年 | 1篇 |
1925年 | 1篇 |
1921年 | 1篇 |
1920年 | 2篇 |
1919年 | 1篇 |
1915年 | 1篇 |
1914年 | 1篇 |
排序方式: 共有200条查询结果,搜索用时 268 毫秒
41.
A. Burck S. Kempf S. Schäfer H. Rotzinger M. Rodrigues T. Wolf L. Gastaldo A. Fleischmann C. Enss 《Journal of Low Temperature Physics》2008,151(1-2):337-344
In the last years metallic magnetic calorimeters (MMC) showed an energy resolution of a few eV for x-rays up to 10 keV. This
makes MMCs a promising and powerful tool for many applications where photons or energetic massive particles have to be detected—like
absolute activity measurements of radioactive isotopes, high resolution x-ray spectroscopy and x-ray fluorescence material
analysis. However, in order to fulfill all requirements of these applications and to allow to reach the maximum resolving
power a consequent micro-fabrication of the MMC detectors is needed. The micro-fabrication of metallic magnetic calorimeters
requires reliable deposition and patterning processes for niobium structures with high critical currents and for paramagnetic
sensors.
As one result of our advances in microstructuring a fully microfabricated MMC which consists of a meander shaped niobium thin
film pickup coil and a 3 μm thick sputter deposited paramagnetic Au:Er temperature sensor will be presented. Deposition of
energy in the paramagnetic sensor causes a rise in temperature and results in a change of magnetization, which is measured
by a low noise high bandwidth dc-SQUID. The sputter deposited Au:Er films we report on are working well and show thermodynamic
properties close to the ones known from bulk material down to temperatures of 45 mK.
相似文献
42.
Moritz Fleischmann Jan Knippers Julian Lienhard Achim Menges Simon Schleicher 《Architectural Design》2012,82(2):44-51
Material behaviour computes form. In the physical world, material form is always inseparably connected to internal constraints and external forces; in the virtual space of digital design, though, form and force are usually treated as separate entities – divided into processes of geometric form generation and subsequent engineering simulation. Using the example of the interdisciplinary ICD/ITKE Research Pavilion, constructed at the University of Stuttgart in 2010, Moritz Fleischmann, Jan Knippers, Julian Lienhard, Achim Menges and Simon Schleicher explain how feedback between computational design, advanced simulation and robotic fabrication expands the design space towards previously unexplored architectural possibilities. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
43.
Recovery of used products is an issue of growing importance due to customer expectations and environmental regulation. As a consequence, companies need to adapt their material management taking into account inbound flows of used products. Corresponding inventory control models have been proposed in literature. In this paper we address the issue of planning stability in a product recovery context. To this end, we consider rolling horizon planning for a stock point facing stochastic demand and product returns. We analyze the impact of the return flow on planning stability and compare the system behaviour with a traditional production environment. We show that structural results derived for traditional inventory models remain valid in a product recovery context. Moreover we discuss counterintuitive effects resulting from interaction between planning stability and stock levels. 相似文献
44.
Peter Zipper Andrs Jnosi Wolfgang Geymayer Elisabeth Ingolic Ernst Fleischmann 《Polymer Engineering and Science》1996,36(4):467-482
Rectangular plates were injection molded from two grades of commercial polypropylene (PP) differing in the molar mass distribution. The mold was mechanically sealed when a desired pressure pi,max (up to 1560 bar) was reached. Samples were taken from each plate at different distances from the gate and were investigated by applying various methods. In spatially resolved wide-angle X-ray studies, the cross section of the sample was scanned with a fine X-ray beam (collimated by a Kratky small-angle camera) and the intensity of scattering was registered by a linear detector as a function of position in the cross section. The evaluation of the scattering data delivered profiles of several parameters, describing the distribution of crystallite modification β-PP and γ-PP, the degree of orientation, the size of crystallites, and interplanar spacing, depending on the distance from surface. These results and those from measurements of birefringence and elongation at break, and from polarization microscopy and transmission electron microscopy, provided details of the layered structures in the plates, at different flow lengths, and allowed far-reaching statements about the influence of molecular properties and processing conditions on the development of texture in the plates. 相似文献
45.
46.
I Arany CM Fleischmann SK Tyring WR Fleischmann 《Canadian Metallurgical Quarterly》1997,119(2):237-240
Photodynamic therapy (PDT) is a treatment modality for malignancies that, uses the accumulation of a photosensitizer in tumor tissue and a subsequent laser light irradiation to selectively destroy tumor cells. Usually PDT is carried out with a hematoporphyrin derivative (HPD) as photosensitizer. Fluorescence characteristics of the HPD Photosan-3 were determined at different concentrations with time-resolved fluorescence spectroscopy. Photosan-3 showed a concentration dependent fluorescence with one fluorescence decay time below a concentration of 10 micrograms/ml, two or three decay times at 50 and 100 micrograms/ml Photosan-3 respectively. These findings confirm results of former studies on other HPD that aggregates and dimers are probably more responsible for the photodynamic effect than monomers. 相似文献
47.
CONTEXT: Cardiac imaging has advanced rapidly, providing clinicians with several choices for evaluating patients with suspected coronary artery disease, but few studies compare modalities directly. OBJECTIVES: To review the contemporary literature and to compare the diagnostic performance of exercise echocardiography (ECHO) and exercise single-photon emission computed tomography (SPECT) imaging in the diagnosis of coronary artery disease. DATA SOURCES: Studies published between January 1990 and October 1997 identified from MEDLINE search; bibliographies of reviews and original articles; and suggestions from experts in each area. STUDY SELECTION: Articles were included if they discussed exercise ECHO and/or exercise SPECT imaging with thallous chloride TI 201 (thallium) or technetium Tc 99m sestamibi for detection and/or evaluation of coronary artery disease, if data on coronary angiography were presented as the reference test, and if the absolute numbers of true-positive, false-negative, true-negative, and false-positive observations were available or derivable from the data presented. Studies performed exclusively in patients after myocardial infarction, after percutaneous transluminal coronary angioplasty, after coronary artery bypass grafting, or with recent unstable coronary syndromes were excluded. DATA EXTRACTION: Clinical variables, technical factors, and test performance were independently extracted by 2 reviewers on a standardized spreadsheet. Discrepancies were resolved by consensus. RESULTS: Forty-four articles met inclusion criteria. In pooled data weighted by the sample size of each study, exercise ECHO had a sensitivity of 85% (95% confidence interval [CI], 83%-87%) with a specificity of 77% (95% CI, 74%-80%). Exercise SPECT yielded a similar sensitivity of 87% (95% CI, 86%-88%) but a lower specificity of 64% (95% CI, 60%-68%). In a summary receiver operating characteristic model comparing exercise ECHO performance to exercise SPECT, exercise ECHO was associated with significantly better discriminatory power (parameter estimate, 1.18; 95% CI, 0.71-1.65), when adjusted for age, publication year, and a setting including known coronary artery disease for SPECT studies. In models comparing the discriminatory abilities of exercise ECHO and exercise SPECT vs exercise testing without imaging, both ECHO and SPECT performed significantly better than exercise testing. The incremental improvement in performance was greater for ECHO (3.43; 95% CI, 2.74-4.11) than for SPECT (1.49; 95% CI, 0.91-2.08). CONCLUSIONS: Exercise ECHO and exercise SPECT have similar sensitivities for the detection of coronary artery disease, but exercise ECHO has better specificity and, therefore, higher overall discriminatory capabilities as used in contemporary practice. 相似文献
48.
U. Ahlers G. Altrogge R. Roski W. Lücke W. Knödel D. Burkhardt P. Stahlknecht B. Fleischmann U. Harms G. Merle R. Trost R. Klein M. G. Zilahi-Szabó 《OR Spectrum》1988,10(3):144-194
Ohne Zusammenfassung 相似文献
49.
50.
The electrophoretic deposition of suitable enamel frits from aqueous suspension and on various metal sheets was investigated. Influence of conductive salts and parameters related to the electrochemistry during deposition show the limits of this coating procedure. 相似文献