全文获取类型
收费全文 | 1368篇 |
免费 | 86篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 10篇 |
综合类 | 3篇 |
化学工业 | 402篇 |
金属工艺 | 22篇 |
机械仪表 | 19篇 |
建筑科学 | 72篇 |
能源动力 | 17篇 |
轻工业 | 210篇 |
水利工程 | 16篇 |
石油天然气 | 1篇 |
无线电 | 105篇 |
一般工业技术 | 220篇 |
冶金工业 | 195篇 |
原子能技术 | 10篇 |
自动化技术 | 155篇 |
出版年
2024年 | 5篇 |
2023年 | 25篇 |
2022年 | 68篇 |
2021年 | 87篇 |
2020年 | 53篇 |
2019年 | 33篇 |
2018年 | 44篇 |
2017年 | 36篇 |
2016年 | 45篇 |
2015年 | 48篇 |
2014年 | 44篇 |
2013年 | 82篇 |
2012年 | 101篇 |
2011年 | 101篇 |
2010年 | 75篇 |
2009年 | 81篇 |
2008年 | 104篇 |
2007年 | 68篇 |
2006年 | 49篇 |
2005年 | 41篇 |
2004年 | 35篇 |
2003年 | 36篇 |
2002年 | 24篇 |
2001年 | 24篇 |
2000年 | 12篇 |
1999年 | 20篇 |
1998年 | 12篇 |
1997年 | 12篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 1篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1976年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有1457条查询结果,搜索用时 15 毫秒
121.
Ana?I.?AndrésEmail author Jens?K.?S.?M?ller Christina?E.?Adamsen Leif?H.?Skibsted 《European Food Research and Technology》2004,219(3):205-210
The effect of high-pressure treatment (200, 400, 600 and 800 MPa) on radical formation in solid samples of dry-cured Iberian ham and in ham slurries was evaluated using the spin-trapping technique and electron spin resonance (ESR) spectroscopy. In addition, hexanal was, as a secondary lipid oxidation product, assessed by gas chromatography. The effect of pressure treatments on ESR signals determined in the spin-trapping assay following pressure treatment in solid samples of dry-cured Iberian ham was not statistically significant. However, the lowest level of pressure applied initiated radical formation and promoted lipid peroxidation, whereas intermediate to high levels of pressure seemed to promote further reaction and disappearance of free radicals. Pressure significantly affected hexanal content in the same way as seen for formation of free radicals. Regarding the slurries prepared from dry-cured ham, pressure significantly increased the tendency of radical formation as seen from the ESR signals and significantly increased the hexanal content. The different pattern between solid ham and ham slurries points toward an initiation mechanism associated with the membrane phospholipids for oxidation. In addition, surface colour (L*, a* and b*
values and percent reflectance values) of non-pressurized and pressurized (200–800 MPa) dry-cured Iberian ham samples was assessed. Non-pressurized samples showed a higher lightness than pressurized samples, and redness significantly decreased with pressure treatment. 相似文献
122.
123.
Many manufacturers in the automobile industry around the world have adopted the just-in-time (JIT) set of management strategies in an effort to improve productivity, efficiency and product quality. This paper provides empirical evidence that supports the idea that JIT manufacturing environments are, in fact, more productive than their non-JIT counterparts. Plant-level cross-sectional data from auto-parts manufacturing firms are used to estimate variable cost functions for a JIT group as well as for a non-JIT group of plants. Differences in cost function characteristics between the two groups are examined and discussed. 相似文献
124.
Eric W. S. Hagan Maria N. Charalambides Christina T. Young Thomas J. S. Learner Stephen Hackney 《Mechanics of Time-Dependent Materials》2009,13(2):149-161
The tensile properties of latex paint films containing TiO2 pigment were studied with respect to temperature, strain-rate and moisture content. The purpose of performing these experiments
was to assist museums in defining safe conditions for modern paintings held in collections. The glass transition temperature
of latex paint binders is in close proximity to ambient temperature, resulting in high strain-rate dependence in typical exposure
environments. Time dependence of modulus and failure strain is discussed in the context of time–temperature superposition,
which was used to extend the experimental time scale. Nonlinear viscoelastic material models are also presented, which incorporate
a Prony series with the Ogden or Neo-Hookean hyperelastic function for different TiO2 concentrations. 相似文献
125.
The neuroscience of memory enriches and expands our theory of psychoanalytic interaction. There are 2 broad modes of processing memory: implicit (never experienced in symbolic form) and explicit (which is symbolic). Memory is not a thing, but a process, activated by a retrieval cue that is either external or internal. Each memory is an amalgam of the memory itself and the retrieval cue. Using these phenomena derived from the neuroscience of memory, the authors argue that (a) the analyst acts as a retrieval cue making any memory a coconstructed phenomenon; (b) each memory is constructed, transformed, and expanded anew, incrementally leading to new networks and change; and (c) implicit memory, lacking symbolic content, is an underutilized component of psychoanalytic attention. Clinical examples are used as illustrations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
126.
Mikhail J. Atallah Christina Lock Black Dan C. Marinescu Howard Jay Siegel Thomas L. Casavant 《Journal of Parallel and Distributed Computing》1992,16(4)
The problem of using the idle cycles of a number of high performance workstations, interconnected by a high speed network, for solving computationally intensive tasks is discussed. The classes of distributed applications examined require some form of synchronization among the subtasks, hence the need for coscheduling to guarantee that subtasks start at the same time and execute at the same pace on a group of workstations. A model of the system is presented that allows the definition of an objective function to be maximized. Then a quadratic time and linear space algorithm is derived for computing the optimal coschedule, for the given model and class of applications addressed. 相似文献
127.
The (YBa2 Cu3 )1−x Nax O7–δ system in the range of x = 0–0.8 was investigated. Experimental data suggest that the sodium doping with x 0.26 does not affect the critical transition temperature Tc , and the crystal structure maintains the orthorhombic lattice with a slightly smaller unit cell. However, sodium doping increases the sintering and grain growth kinetics, resulting in a higher superconducting phase volume and an enhanced Meissner effect. It also lowers the processing temperaturel. The experimental data also suggest that the sodium atoms diffuse into the superconducting YBa2 Cu3 O7−δ crystallites, which stabilizes the orthorhombic phase. The transition temperature (ortho-rhombic to tetragonal) in sodium-doped materials increases with the increasing concentration of sodium. 相似文献
128.
129.
130.
Henneke Christina M.; Danson Michael J.; Hough David W.; Osguthorpe David J. 《Protein engineering, design & selection : PEDS》1989,2(8):597-604
The alignment of Escherichia coli citrate synthase to pig heartcitrate synthase and the multiple alignment of the known sequencesof the citrate synthase family of enzymes have been performedusing six different amino acid similarity scoring matrices anda large range of gap penalty ratios for insertions and deletionsof amino acids. The alignment studies have been performed asthe first step in a project aimed at homology modelling E.colicitrate synthase (a hexamer) from pig heart citrate synthase(a dimer) in a molecular modelling approach to the study ofmulti-subunit enzymes. The effects of several important variablesin producing realistic alignments have been investigated. Thedifference between multiple alignment of the family of enzymesversus simple pairwise alignment of the pig heart and E.coliproteins was explored. The effects of initial separate multiplealignments of the most highly related or most homologous speciesof the family of enzymes upon a subsequent pairwise alignmentbetween species was evaluated. The value of fingerprintingcertain residues to bias the alignment in favour of matchingthose residues, as well as the worth of the computerized approachcompared to an intuitive alignment technique, were assessed. 相似文献