全文获取类型
收费全文 | 232篇 |
免费 | 4篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 30篇 |
金属工艺 | 4篇 |
机械仪表 | 9篇 |
建筑科学 | 7篇 |
能源动力 | 9篇 |
轻工业 | 24篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 41篇 |
一般工业技术 | 30篇 |
冶金工业 | 35篇 |
原子能技术 | 5篇 |
自动化技术 | 34篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 7篇 |
2013年 | 17篇 |
2012年 | 21篇 |
2011年 | 11篇 |
2010年 | 7篇 |
2009年 | 18篇 |
2008年 | 7篇 |
2007年 | 9篇 |
2006年 | 15篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1965年 | 2篇 |
排序方式: 共有236条查询结果,搜索用时 15 毫秒
71.
I Tezcan W Xu A Gurgey M Tuncer M Cetin C Oner S Yetgin F Ersoy G Aizencang KH Astrin RJ Desnick 《Canadian Metallurgical Quarterly》1998,92(11):4053-4058
The long-term biochemical and clinical effectiveness of allogenic bone marrow transplantation (BMT) was shown in a severely affected, transfusion-dependent 18-month-old female with congenital erythropoietic porphyria (CEP), an autosomal recessive inborn error of heme biosynthesis resulting from mutations in the uroporphyrinogen III synthase (URO-synthase) gene. Three years post-BMT, the recipient had normal hemoglobin, markedly reduced urinary porphyrin excretion, and no cutaneous lesions with unlimited exposure to sunlight. The patient was homoallelic for a novel URO-synthase missense mutation, G188R, that expressed less than 5% of mean normal activity in Escherichia coli, consistent with her transfusion dependency. Because the clinical severity of CEP is highly variable, ranging from nonimmune hydrops fetalis to milder, later onset forms with only cutaneous lesions, the importance of genotyping newly diagnosed infants to select severely affected patients for BMT is emphasized. In addition, the long-term effectiveness of BMT in this patient provides the rationale for future hematopoietic stem cell gene therapy in severely affected patients with CEP. 相似文献
72.
Oral fluids are convenient alternatives to blood sampling for evaluating significant metabolic components. Two forms of oral fluids, oral mucosal transudates (OMT) and saliva, were collected and compared for content of soluble products of immune activation. The data confirm that OMT and saliva represent distinct body fluids. The concentrations, outputs, and analyte/protein ratios of beta-2-microglobulin (beta2M), soluble tumor necrosis factor alpha receptor II (sTNFalphaRII), and neopterin were measured. Both the OMT and the saliva of most of the individuals in the control healthy populations had measurable levels of all three activation markers. When the immune system is activated, as in human immunodeficiency virus (HIV) infection, the levels of beta2M and sTNFalphaRII are increased in both OMT and saliva compared to those in a healthy control population. OMT levels correlated better with levels in serum than did saliva and appear to reflect systemic immune activation in HIV infection. Because acquisition of oral fluids is noninvasive and easily repeatable, measurement of beta2M and/or sTNFalphaRII content in OMT could be useful in the assessment of disease activity in patients with HIV infection or chronic inflammatory diseases. 相似文献
73.
In this paper, a simple natural convection heat-transfer model for a safety rod placed in a perforated guide tube is proposed. The geometry is typical of the Savannah River K reactor. The proposed model for the rod and the perforated guide-tube assembly is benchmarked against prototypical test data obtained by Idaho National Engineering Laboratory. The results showed that the proposed model was in good agreement with the experimental data except at very high temperatures where the model slightly underpredicted the rod and tube temperatures. By evaluating the thermal conductivity of the fluid (air) at the wall temperature, the prediction of the high temperature natural convection data was further improved. 相似文献
74.
Prof. Dr. techn. Dipl.-Ing. Ilhami Cetin 《Electrical Engineering (Archiv fur Elektrotechnik)》1965,50(2):105-111
Übersicht Angesichts der entscheidenden Bedeutung der magnetischen Nichtlinearität in der Theorie und Anwendung der Elektrotechnik scheint eine gründlichere Behandlung der Induktivitäten angebracht. Die Arbeit erläutert zuerst die Definitionen, die Änderung und die Anwendung der als Oberbegriff genommenen Grundinduktivitäten bei Gleichstrom. Diese sind die Fluß-, die Differential- und die Energieinduktivität. Dann kommen die drei herkömmlichen Möglichkeiten für die Verwendung der Induktivitäten bei periodischem Strom zur Sprache. Mit der Differentialinduktivität kann man die verhältnismäßig kleinen Änderungen der Variablen Strom und Fluß im ganzen erfassen. Die Schwingungsinduktivitäten sind über die ganze Periode, jedoch nur für eine bestimmte Harmonische gültig. Welche physikalische Definition der Induktivität bei periodischem Strom im nichtlinearen Teil der magnetischen Kennlinie gilt, scheint bisher nicht untersucht zu sein.
Mit 2 Textabbildungen 相似文献
Summary In view of the overwhelming importance of the magnetic non-linearity in the theory and application of electrical engineering, a more thorough-going treatment of inductances seems to be desirable. The paper deals at first with the definitions, the variation and the application of basic inductances at d. c. which are considered as an upper concept. These are the flux, the incremental and the energy inductances. Then the three usual possibilities for using the inductances for periodic current are discussed. The incremental inductance includes in the whole the relatively small variations of the variables current and flux. The inductances for harmonics are valid over the whole period, but only for a definitecouple of harmonics, without being associated with the flux as a whole. Which physical definition of inductance is valid for periodic current for the nonlinear part of the saturation characteristic, seems hitherto not to be investigated.
Mit 2 Textabbildungen 相似文献
75.
Computational challenges of viscous incompressible flows 总被引:1,自引:0,他引:1
Over the past 30 years, numerical methods and simulation tools for incompressible flows have been advanced as a subset of the computational fluid dynamics (CFD) discipline. Although incompressible flows are encountered in many areas of engineering, simulation of compressible flow has been the major driver for developing computational algorithms and tools. This is probably due to the rather stringent requirements for predicting aerodynamic performance characteristics of flight vehicles, while flow devices involving low-speed or incompressible flow could be reasonably well designed without resorting to accurate numerical simulations. As flow devices are required to be more sophisticated and highly efficient, CFD tools become increasingly important in fluid engineering for incompressible and low-speed flow. This paper reviews some of the successes made possible by advances in computational technologies during the same period, and discusses some of the current challenges faced in computing incompressible flows. 相似文献
76.
Babur Ozcelik Emel KuramM. Huseyin Cetin Erhan Demirbas 《Tribology International》2011,44(12):1864-1871
Experimental studies on the performances of both new developed environmental friendly vegetable based cutting fluids (refined sunflower and canola oils) including different percentage of extreme pressure (EP) additive and two commercial cutting fluids (semi-synthetic and mineral cutting fluids) in turning processes were reported in this work. Performances of cutting fluids were compared with respect to surface roughness, cutting and feed forces and tool wear during longitudinal turning of AISI 304L. Experimental results were also compared with dry cutting conditions. The results indicated that 8% of EP included canola based cutting fluid performed better than the rest. 相似文献
77.
Recycling of inorganic waste in monolithic and cellular glass‐based materials for structural and functional applications 下载免费PDF全文
Acacio Rincón Mauro Marangoni Suna Cetin Enrico Bernardo 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2016,91(7):1946-1961
The stabilization of inorganic waste of various nature and origin, in glasses, has been a key strategy for environmental protection for the last decades. When properly formulated, glasses may retain many inorganic contaminants permanently, but it must be acknowledged that some criticism remains, mainly concerning costs and energy use. As a consequence, the sustainability of vitrification largely relies on the conversion of waste glasses into new, usable and marketable glass‐based materials, in the form of monolithic and cellular glass‐ceramics. The effective conversion in turn depends on the simultaneous control of both starting materials and manufacturing processes. While silica‐rich waste favours the obtainment of glass, iron‐rich wastes affect the functionalities, influencing the porosity in cellular glass‐based materials as well as catalytic, magnetic, optical and electrical properties. Engineered formulations may lead to important reductions of processing times and temperatures, in the transformation of waste‐derived glasses into glass‐ceramics, or even bring interesting shortcuts. Direct sintering of wastes, combined with recycled glasses, as an example, has been proven as a valid low‐cost alternative for glass‐ceramic manufacturing, for wastes with limited hazardousness. The present paper is aimed at providing an up‐to‐date overview of the correlation between formulations, manufacturing technologies and properties of most recent waste‐derived, glass‐based materials. © 2016 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献
78.
Emel Kuram Babur Ozcelik M. Huseyin Cetin Erhan Demirbas Sule Askin 《Lubrication Science》2013,25(1):39-52
In this study, performances of four different types of vegetable‐based cutting fluids (VBCFs) over a commercial mineral cutting fluid were evaluated for machinability of Al 7075‐T6. Lubrication properties of VBCFs were improved with additive of extreme pressure. Cutting force and tool wear data were obtained for performance analyses of cutting fluids during longitudinal turning of Al 7075‐T6. Cutting, feed and radial forces indicated 1.70–38.25% improvements for VBCFs over the commercial mineral cutting fluid. The lowest average values of flank and nose wears obtained with blended cutting fluid containing 12% of extreme pressure were 0.09 and 0.10 mm, respectively, whereas these values for the commercial mineral cutting fluid were 0.18 and 0.15 mm. The scanning electron microscope results showed adherence of workpiece material occurred on rake and flank faces, and flank and nose wears were the dominant wear modes. It was found that performances of VBCFs during turning of Al 7075‐T6 were better than that of the commercial mineral cutting fluid. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
79.
Umran Elmas Fevzi Bedir Muhammet Kayfeci 《International Journal of Hydrogen Energy》2018,43(23):10741-10754
In this study, hydrogen storage capacity were analyzed by considering hydrogen absorption test rig depending on some reactor design parameters such as metal hydride particle size, having fins at the tank, hydrogen inlet pressure, inlet radius of the tank, coolant temperature, general convective heat transfer coefficient and wall thickness of the tank. In the specified design parameters of the hydrogen storage system we put these in COMSOL Multiphysics 5.1 software to obtain some approaches in the large scale. All parameters were analyzed using three different metal hydrides of the MmNi4,6Al0,4, LaNi4.75Al0.25 and LaNi5. Some parameters like temperature distribution inside the tank, amount of the hydrogen mass to be stored in the tank, the time durations of them and the variations of the equilibrium pressure of the system were optimized. 相似文献
80.
N. Ekem S. Korkmaz S. Pat M.Z. Balbag E.N. Cetin M. Ozmumcu 《International Journal of Hydrogen Energy》2009
ZnO thin films were deposited with RF sputtering using pure Zn target. In order to generate oxidation process of Zn, Ar:O2 gas mixing in (9:1), (7:3) and (5:5) ratios of Ar:O2 was used. To characterize ZnO thin films thickness and transparency were measured using optical method, and refractive index and band gap energies were calculated. Electrical conductivity of the ZnO thin films was also determined. AFM images were used to determine surface morphology of produced ZnO thin films. 相似文献