全文获取类型
收费全文 | 739篇 |
免费 | 47篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 17篇 |
化学工业 | 200篇 |
金属工艺 | 5篇 |
机械仪表 | 20篇 |
建筑科学 | 31篇 |
能源动力 | 28篇 |
轻工业 | 99篇 |
水利工程 | 6篇 |
石油天然气 | 1篇 |
无线电 | 48篇 |
一般工业技术 | 117篇 |
冶金工业 | 69篇 |
原子能技术 | 4篇 |
自动化技术 | 142篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 35篇 |
2021年 | 47篇 |
2020年 | 25篇 |
2019年 | 24篇 |
2018年 | 33篇 |
2017年 | 28篇 |
2016年 | 30篇 |
2015年 | 22篇 |
2014年 | 33篇 |
2013年 | 52篇 |
2012年 | 28篇 |
2011年 | 40篇 |
2010年 | 37篇 |
2009年 | 45篇 |
2008年 | 23篇 |
2007年 | 31篇 |
2006年 | 28篇 |
2005年 | 14篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 12篇 |
1998年 | 30篇 |
1997年 | 14篇 |
1996年 | 13篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
排序方式: 共有787条查询结果,搜索用时 8 毫秒
61.
Giacomo Veneri Pamela Federighi Francesca Rosini Antonio Federico Alessandra Rufa 《Computers in human behavior》2010
We describe an interactive gaze-contingent display (GCD) applied to clinical applications; the system uses a simple texture hole to inhibit peripheral vision, to test and stress overt mechanisms of visual searching in normal subjects. The correct use of GCD in vision research is affected by tremor of the hole, due to system noise, nystagmus, eye blinking, calibration and subject reactivity. These issues compromise the execution of task. In order to obtain a stable GCD hole, we implemented a predictive gaze-contingent display (PGCD), fitting through dispersion of fixations and modulating a filter. The paper describes the PGCD and compare it with the common technique, providing evidence that humans fit exploration based on the characteristics of the computer system; in particular we found significant difference applying PGCD or a simple finite impulse response filter. We suggest that a correct human–computer interaction applied to neuropsychological context must be developed taking in consideration both technical point of view and human behavior. 相似文献
62.
63.
Tested the hypothesis that poor performance among schizophrenics (SCZs) is associated with less orienting to task-relevant stimuli and more orienting to task-irrelevant stimuli, interpreting the orienting response as a call for controlled processing resources. 32 SCZs (aged 20–65 yrs) and 32 age- and sex-matched controls were exposed to a signaled reaction time (RT) task in which one tone was followed by an imperative noise stimulus and a different tone signaled nothing. During one phase of the experiment, distracting visual stimuli were presented both between and during RT trials. Controls differentiated between the signal and nonsignal tones in all measures and showed rapid habituation to the distracting visual stimuli. The SCZs showed slow RTs, less overall responding than controls, and limited differential responses to signal and nonsignal stimuli. For the responses to visual distractors, however, the SCZs showed significantly slower habituation than the controls, confirming their inefficient orienting style. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
64.
Dorothea F K Rawn Sue C Quade J Brian Shields Giacomo Conca Wing-Fung Sun Gladys M A Lacroix Mark Smith André Fouquet André Bélanger 《Food Additives & Contaminants》2007,24(2):149-155
Apple trees in an orchard in Quebec, Canada were treated, following label directions, with the fungicide captan (1,2,3,6-tetrahydro-N-(trichloromethylthio)phthalimide) during the 2003 agricultural season. A total of 142 apples from three rows of trees were selected for determination of captan by GC/MS. Individual apples were found to contain captan levels ranging from 16.9 to 6350 ng g-1. Only two individual apple samples exceeded the Canadian maximum residue limit (5000 ng g-1) for captan in apples. Six composite samples, comprising half portions of eight individual apples, were analysed from each of the three experimental rows. Composite samples ranged in concentration from 166 to 2620 ng g-1. The greatest uncertainty associated with the measured concentrations was due to variability among apples rather than the measurement of residue levels. 相似文献
65.
Junction leakage current degradation under high temperature reverse-bias stress induced by band-defect-band tunnelling in power VDMOS 总被引:2,自引:0,他引:2
A deep analysis of the intrinsic junction and surface currents in power vertically diffused MOS devices with sub-micrometer channel length and thin gate oxide has been carried on after a typical reliability high temperature reverse bias (HTRB) stress. A reference set of gated diodes has also been examined in order to better understand the onset and evolution of post-stress leakage degradation. A comparison among complete MOSs, single body diodes and enriched diodes allows to highlight the role played by the point defectivity both at gate interface and in the bulk silicon close to the junction surface. We found that the typical interface defects involved in the leakage degradation are shallow traps and can be de-populated simply by a thermally activated mechanism. More specifically, the main degradation mechanism relies to band-defect-band tunneling localized at the surface drain/body junction where an intrinsic n-i-p region evolves due to a bird’s beak lateral profile of the body diffusion. We have demonstrated that the most important contribution to the activation of the precursor defect sites is given by the transverse electrical field that develops just below the SiO2/Si interface within the n-i-p region during the stress. 相似文献
66.
67.
Marco Leonesio Paolo Parenti Alberto Cassinari Giacomo Bianchi 《The International Journal of Advanced Manufacturing Technology》2014,72(9-12):1347-1360
In this paper, a particular kind of non-regenerative instability in surface grinding is studied. Clear evidences have been collected suggesting that vibrations can occur suddenly even during the first grinding pass, just after wheel dressing. These circumstances exclude workpiece and wheel surface regeneration as instability origin, whereas both surfaces have to be considered initially smooth. On these bases, the stability of the dynamic system constituted by an oscillating ideal wheel (namely without waviness on the surface) immerged in a positional and velocity-dependent process force field has been studied, demonstrating that, under particular conditions, the force field generates an unstable behaviour. The instability occurrence is strictly related to the oscillation direction of the wheel centre, according to the mode shape associated to the dominant resonance, with respect to the direction of the grinding force (identified by the ratio between its tangential and normal components). The analysis leads to the identification of a simple necessary condition for instability occurrence. The analytical results are confirmed by time-domain grinding simulations and compared with experimental evidences. 相似文献
68.
We have constructed new yeast vectors for targeted integration and conditional expression of any sequence at the Saccharomyces cerevisiae TYR1 locus which becomes disrupted. We show that vector integration is not neutral, causing prototrophy for tyrosine and auxotrophy for the vector's selectable marker (uracil or leucine, depending on the vector used). This feature allows a double screening of transformed yeast cells, improving the identification of colonies with the desired chromosomal structure. The GAL10 gene promoter has been added to drive conditional expression of cloned sequences. Using these vectors, chromosomal structure verification of recombinant clones is no longer necessary, since the noise of non-homologous recombination, as well as spontaneous reversion of the selected phenotype, can easily be identified. The ability of the vector to conditionally control gene expression has been confirmed using the gene for the green fluorescent protein (GFP) as a reporter. 相似文献
69.
Zirconium and hafnium oxide interface with silicon: Computational study of stress and strain effects
Computations of the periodic double-interface MO2/Si (M = Zr and Hf) systems using density functional theory (DFT) demonstrate that very thin epitaxial MO2 layers at silicon (1 0 0) surface adopt anatase-like structure with six-coordinate M atoms, while tetragonal-like MO2 structure with seven-coordinated M atoms has a lower stability (metastable). This results from a closer match between Si(1 0 0) surface unit cell and anatase-like ZrO2 and HfO2 leading to the overall stress reduction if MO2 adopts the anatase-like structure on silicon. In agreement with the previous study of Gavartin et al. [Gavartin, Fonseca, Bersuker, Shluger, Microelectron. Eng. 80 (2005) 412–415] formation of oxygen vacancy at the interface is demonstrated to be lower than in bulk film. This result appears to be independent from the film or interface structure but originates from the energy balance between M–O, M–M, Si–O and M–Si bonds, as revealed by a simple molecular model. 相似文献
70.