全文获取类型
收费全文 | 597篇 |
免费 | 47篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 143篇 |
金属工艺 | 31篇 |
机械仪表 | 31篇 |
建筑科学 | 19篇 |
矿业工程 | 3篇 |
能源动力 | 19篇 |
轻工业 | 122篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 23篇 |
一般工业技术 | 136篇 |
冶金工业 | 6篇 |
原子能技术 | 5篇 |
自动化技术 | 98篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 17篇 |
2020年 | 14篇 |
2019年 | 15篇 |
2018年 | 26篇 |
2017年 | 13篇 |
2016年 | 25篇 |
2015年 | 26篇 |
2014年 | 43篇 |
2013年 | 109篇 |
2012年 | 37篇 |
2011年 | 28篇 |
2010年 | 53篇 |
2009年 | 43篇 |
2008年 | 34篇 |
2007年 | 17篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 5篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1970年 | 2篇 |
1962年 | 2篇 |
1961年 | 3篇 |
1957年 | 2篇 |
排序方式: 共有648条查询结果,搜索用时 31 毫秒
31.
Jiří Čulík Marie Jurková Tomáš Horák Pavel Čejka Vladimír Kellner Josef Dvořák Pavel Karásek Michal Roth 《Journal of the Institute of Brewing》2009,115(3):220-225
The EBC method 7.7, currently used for determination of bitter acids in hop products, is a time‐consuming and laborious extraction technique. In this paper, our aim was to propose a new extraction method based on Pressurized Solvent Extraction (PSE) sometimes also called Pressurized Fluid Extraction (PFE) or Accelerated Solvent Extraction (ASE). Compared to conventional extractions, PSE offers a number of important benefits. PSE on OnePSE® automated extractor was used for extraction of α‐ and β‐acids from hops and hop products and the parameters influencing extraction efficiency and the influence of the sample preparation method were studied. The quantitative determination of α‐ and β‐acids in the extracts was accomplished by using an HPLC apparatus equipped with diode array detector. The experimental results were compared with those obtained by the standard EBC 7.7 method and the two methods were found to be fully compatible 相似文献
32.
Nina Radić Bratislav M. Obradović Mirjana Kostić Biljana Dojčinović Milorad M. Kuraica Mirko Černák 《Surface & coatings technology》2012
The aim of this work is plasma activation of nonwoven polypropylene (PP) using two different ambient air plasma sources: volume dielectric barrier discharge (DBD) and diffuse coplanar surface barrier discharge (DCSBD) and its functionalization by silver ion deposition. 相似文献
33.
Although experimental observations determine the martensite structure of NiTi as monoclinic (B19′), ab-initio calculations show that, after a full optimization of the lattice, the ideal martensite structure relaxes into orthorhombic B33 one. This paper presents a first principles investigation of the structure of (100) compound twins in martensite. The results obtained by means of two different computational codes show that the optimized structure of twin cells is very close to that of B19′ martensite. This indicates that twinning can significantly contribute to mechanisms stabilizing the B19′ structure in real martensite samples. 相似文献
34.
Tomáš Horák Jiří Čulík Vladimír Kellner Marie Jurková Pavel Čejka 《Journal of the Institute of Brewing》2009,115(3):214-219
Dominant trends in analytical chemistry include miniaturization in sample preparation techniques and faster run times to provide high‐throughput screening, fast process monitoring and fast method development. This study focused on the application of narrow bore gas chromatographic capillary columns, 0.18 mm internal diameter, for brewing analyses. On these capillary columns, faster analyses could be performed compared to conventional GC capillary columns using 0.32 to 0.53 mm internal diameters. The robustness of the state‐of‐the‐art faster capillary gas chromatography, without compromising resolution, has been demonstrated with the analyses of beer flavour compounds such as lower and higher alcohols, esters and other volatile compounds such as acetaldehyde and dimethyl sulphide in beer. These methods were able to reduce sample run times by 60%. 相似文献
35.
36.
Justin Činkelj Roman Kamnik Peter Čepon Matjaž Mihelj Marko Munih 《Automation in Construction》2010,19(7):954-963
Automatization is supposed to improve working conditions and safety in the construction industry, as it already did in manufacturing industries. This paper presents the development of a robotic control system for a commercially available hydraulic telescopic handler. The target application for the telescopic handler is semi-automated assembly of facade panels. The base handler was upgraded with two additional hydraulic axes, position sensors and closed-loop control system, while the original handler safety assurance mechanisms were preserved. The control approach is based on a PI controller with velocity feedforward and valve overlap compensation. The direct and inverse kinematic models of handler mechanism were developed to enable control of end-effector motion along a straight line in the Cartesian coordinate system. The motion performances were evaluated following the ISO 9283 standard with payload of 2000 kg. Results show the repeatability of positioning bellow 7.0 mm and the straight line tracking error smaller than 63 mm. 相似文献
37.
Lidija Čuček Hon Loong Lam Jiří J. Klemeš Petar S. Varbanov Zdravko Kravanja 《Clean Technologies and Environmental Policy》2010,12(6):635-645
This article presents a method for the synthesis of regional renewable energy supply chains, based on Mixed-Integer Linear
Programming (MILP). This method addresses the challenges presented by biomass resources. The main challenges are the distributive
and varied availabilities regarding both location and time. This work also aims to maximise the economically viable utilisation
of resources, accounting for the competition between energy and food production. A four-layer supply chain superstructure
has been developed, which includes the harvesting, preparation, core processing and distribution of products. This considered
system’s boundaries involve a region, which is then divided into zones for optimising conversion operations and transportation
flows. An MILP model has been formulated with profit maximisation as the optimisation criterion. The environmental impact
is evaluated by the carbon footprint. The sensitivity of the optimal solutions is analysed for different regions’ sizes, transportation
costs, pre-processing alternatives and the co-production of food and energy. 相似文献
38.
Zuzana Živcová Martin Černý Willi Pabst Eva Gregorová 《Journal of the European Ceramic Society》2009,29(13):2765-2771
The elastic properties, in particular the tensile modulus (Young's modulus) and Poisson ratio, of porous alumina, zirconia, and alumina–zirconia composite ceramics are studied using the resonance frequency method and the results compared with theoretical predictions. Starch is used as a pore-forming agent, so that the resulting microstructure is essentially of the matrix-inclusion type (with large bulk pores, connected by small throats when a percolation threshold is exceeded). It is found that for this type of microstructure the porosity dependence of the Young's modulus is significantly below the upper Hashin–Shtrikman bound and the power-law prediction; it corresponds well, however, to a recently proposed exponential relation and to an empirical volume-weighted average of the upper and lower Hashin–Shtrikman bounds. Results for all three types of ceramics indicate that – in the porosity range considered, i.e. up to approximately 50% – the Poisson ratio depends only slightly on porosity. 相似文献
39.
40.
The results of zeta-potential determination using the electro-osmotic method in dilute (10–3 mol dm–3) solutions of NH4Cl and ZnCl2 and diffusion parameters measured in 20% NH4Cl and 30% ZnCl2 solutions are presented. In both cases cellulosic membrane separators from different manufacturers, already in practical usage in Leclanché cells, were examined. From the measured data, diffusion potentials were calculated and compared with experimental values. Transport numbers calculated from diffusion potentials are compared to values in free solution (i.e. without a membrane). The relevance of these parameters to the role of cellulosic separators in Leclanché-type cells is briefly discussed. 相似文献