全文获取类型
收费全文 | 3297篇 |
免费 | 127篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 36篇 |
综合类 | 14篇 |
化学工业 | 1070篇 |
金属工艺 | 61篇 |
机械仪表 | 41篇 |
建筑科学 | 184篇 |
矿业工程 | 4篇 |
能源动力 | 55篇 |
轻工业 | 320篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
无线电 | 177篇 |
一般工业技术 | 677篇 |
冶金工业 | 319篇 |
原子能技术 | 25篇 |
自动化技术 | 438篇 |
出版年
2023年 | 39篇 |
2022年 | 57篇 |
2021年 | 73篇 |
2020年 | 43篇 |
2019年 | 61篇 |
2018年 | 50篇 |
2017年 | 50篇 |
2016年 | 85篇 |
2015年 | 88篇 |
2014年 | 101篇 |
2013年 | 165篇 |
2012年 | 171篇 |
2011年 | 206篇 |
2010年 | 152篇 |
2009年 | 165篇 |
2008年 | 170篇 |
2007年 | 155篇 |
2006年 | 138篇 |
2005年 | 129篇 |
2004年 | 102篇 |
2003年 | 74篇 |
2002年 | 70篇 |
2001年 | 61篇 |
2000年 | 61篇 |
1999年 | 73篇 |
1998年 | 83篇 |
1997年 | 64篇 |
1996年 | 42篇 |
1995年 | 55篇 |
1994年 | 50篇 |
1993年 | 35篇 |
1992年 | 42篇 |
1991年 | 46篇 |
1990年 | 27篇 |
1989年 | 33篇 |
1988年 | 34篇 |
1987年 | 33篇 |
1986年 | 25篇 |
1985年 | 26篇 |
1984年 | 32篇 |
1983年 | 17篇 |
1982年 | 12篇 |
1981年 | 24篇 |
1980年 | 18篇 |
1979年 | 20篇 |
1978年 | 17篇 |
1977年 | 16篇 |
1976年 | 28篇 |
1975年 | 19篇 |
1974年 | 16篇 |
排序方式: 共有3426条查询结果,搜索用时 21 毫秒
61.
In 5 experiments, the authors tested whether the processing of nonconscious spatial stimulus information depends on a prior intention. This test was conducted with the metacontrast dissociation paradigm. Experiment 1 demonstrated that masked primes that could not be discriminated above chance level affected responses to the visible stimuli that masked them. Experiments 2 and 3 showed that this effect was abolished when the task instruction was changed in such a way that the primes ceased to be task relevant. Experiments 4 and 5 demonstrated that a prime's effect depended on whether it was associated with the same response as the target or with an opposite response. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
62.
Low temperature silicon direct bonding for application in micromechanics: bonding energies for different combinations of oxides 总被引:3,自引:0,他引:3
Gertrud Kräuter Andreas Schumacher Ulrich Gösele 《Sensors and actuators. A, Physical》1998,70(3):100-275
Plain or structured hydrophillic silicon wafers covered with native oxide or with thermally grown oxide layers have been directly bonded at room temperature; afterwards, the samples were annealed at 100°C to 400°C. There is a significant difference in the observed bonding energy depending on the wafer pairing chosen. If one or both wafers are covered with a native oxide layer, high bonding strengths are reached even at low temperatures. This can be explained by the different diffusion behaviour of water molecules through a thick thermal oxide layer on one hand, and through a thin native oxide layer on the other hand. Two different methods for the activation of the wafer surfaces just prior to bonding are described. 相似文献
63.
64.
The performance of older adults and depressed people on linear order reasoning is hypothesized to be best explained by different theoretical models. Whereas depressed younger adults are found to be impaired in generative inference making, older adults are well capable of making such inferences but exhibit problems with working memory (Experiments 1 and 2). Restriction of the available study time impairs reasoning by nondepressed control participants and. as such, proves to be a good model of older adults' but not depressed participants' limitations (Experiment 3). These results are replicated comparing depressed and older participants with a control group in the same study, providing increased power and linking the results to additional control measures of processing speed and working memory (Experiment 4). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
Simon effects might partly reflect stimulus-triggered response activation. According to the response-discrimination hypothesis, however, stimulus-triggered response activation shows up in Simon effects only when stimulus locations match the top-down selected spatial codes used to discriminate between alternative responses. Five experiments support this hypothesis. In Experiment 1, spatial codes of each response differed by horizontal and vertical axis position, yet one axis discriminated between alternative responses, whereas the other did not. Simon effects resulted for targets on discriminating axes only. In Experiment 2, both spatial axes discriminated between responses, and targets on both axes produced Simon effects. In Experiment 3, Simon effects resulted for a spatial choice-reaction task but not for a go/no-go task. Even in the go/no-go task, a Simon effect was restored when a two-choice reaction task preceded the go/no-go task (Experiment 4) or when participants initiated trials with responses spatially discriminated from the go response (Experiment 5). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
66.
We propose a semantics for the -quantifier of Miller and Tiu. First we consider the case for classical first-order logic. In this case, the interpretation is close to standard Tarski-semantics and completeness can be shown using a standard argument. Then we put our semantics into a broader context by giving a general interpretation of in categories with binding structure. Since categories with binding structure also encompass nominal logic, we thus show that both -logic and nominal logic can be modelled using the same definition of binding. As a special case of the general semantics in categories with binding structure, we recover Gabbay & Cheney's translation of FOλ into nominal logic. 相似文献
67.
Christian Friebe Martin D. Hager Andreas Winter Ulrich S. Schubert 《Advanced materials (Deerfield Beach, Fla.)》2012,24(3):332-345
Electropolymerization represents a suitable and well‐established approach for the assembly of polymer structures, in particular with regard to the formation of thin, insoluble films. Utilization of monomers that are functionalized with metal complex units allows the combination of structural and functional benefits of polymers and metal moieties. Since a broad range of both electropolymerizable monomers and metal complexes are available, various structures and, thus, applications are possible. Recent developments in the field of synthesis and potential applications of metal‐functionalized polymers obtained via electropolymerization are presented, highlighting the significant advances in this field of research. 相似文献
68.
Rami T. ElAfandy Ayman F. AbuElela Pawan Mishra Bilal Janjua Hassan M. Oubei Ulrich Büttner Mohammed A. Majid Tien Khee Ng Jasmeen S. Merzaban Boon S. Ooi 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(7)
Knowledge of materials' thermal‐transport properties, conductivity and diffusivity, is crucial for several applications within areas of biology, material science and engineering. Specifically, a microsized, flexible, biologically integrated thermal transport sensor is beneficial to a plethora of applications, ranging across plants physiological ecology and thermal imaging and treatment of cancerous cells, to thermal dissipation in flexible semiconductors and thermoelectrics. Living cells pose extra challenges, due to their small volumes and irregular curvilinear shapes. Here a novel approach of simultaneously measuring thermal conductivity and diffusivity of different materials and its applicability to single cells is demonstrated. This technique is based on increasing phonon‐boundary‐scattering rate in nanomembranes, having extremely low flexural rigidities, to induce a considerable spectral dependence of the bandgap‐emission over excitation‐laser intensity. It is demonstrated that once in contact with organic or inorganic materials, the nanomembranes' emission spectrally shift based on the material's thermal diffusivity and conductivity. This NM‐based technique is further applied to differentiate between different types and subtypes of cancer cells, based on their thermal‐transport properties. It is anticipated that this novel technique to enable an efficient single‐cell thermal targeting, allow better modeling of cellular thermal distribution and enable novel diagnostic techniques based on variations of single‐cell thermal‐transport properties. 相似文献
69.
70.
Sheikh M. Uddin Tanvir Mahmud Christoph Wolf Carsten Glanz Ivica Kolaric Christoph Volkmer Helmut Höller Ulrich Wienecke Siegmar Roth Hans-Jörg Fecht 《Composites Science and Technology》2010
Utilizing the extra-ordinary properties of carbon nanotube (CNT) in metal matrix composite (MMC) for macroscopic applications is still a big challenge for science and technology. Very few successful attempts have been made for commercial applications due to the difficulties incorporating CNTs in metals with up-scalable processes. CNT reinforced copper and copper alloy (bronze) composites have been fabricated by well-established hot-press sintering method of powder metallurgy. The parameters of CNT–metal powder mixing and hot-press sintering have been optimized and the matrix materials of the mixed powders and composites have been evaluated. However, the effect of shape and size of metal particles as well as selection of carbon nanotubes has significant influence on the mechanical and electrical properties of the composites. The hardness of copper matrix composite has improved up to 47% compared to that of pure copper, while the electrical conductivity of bronze composite has improved up to 20% compared to that of the pure alloy. Thus carbon nanotube can improve the mechanical properties of highly-conductive low-strength copper metals, whereas in low-conductivity high-strength copper alloys the electrical conductivity can be improved. 相似文献