全文获取类型
收费全文 | 1048篇 |
免费 | 32篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
综合类 | 3篇 |
化学工业 | 352篇 |
金属工艺 | 14篇 |
机械仪表 | 11篇 |
建筑科学 | 60篇 |
矿业工程 | 2篇 |
能源动力 | 27篇 |
轻工业 | 219篇 |
水利工程 | 10篇 |
石油天然气 | 3篇 |
无线电 | 37篇 |
一般工业技术 | 153篇 |
冶金工业 | 86篇 |
原子能技术 | 6篇 |
自动化技术 | 91篇 |
出版年
2023年 | 8篇 |
2022年 | 35篇 |
2021年 | 55篇 |
2020年 | 11篇 |
2019年 | 18篇 |
2018年 | 17篇 |
2017年 | 18篇 |
2016年 | 27篇 |
2015年 | 23篇 |
2014年 | 26篇 |
2013年 | 96篇 |
2012年 | 55篇 |
2011年 | 64篇 |
2010年 | 47篇 |
2009年 | 39篇 |
2008年 | 54篇 |
2007年 | 50篇 |
2006年 | 48篇 |
2005年 | 43篇 |
2004年 | 31篇 |
2003年 | 28篇 |
2002年 | 35篇 |
2001年 | 6篇 |
2000年 | 17篇 |
1999年 | 13篇 |
1998年 | 20篇 |
1997年 | 14篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 14篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1983年 | 3篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1955年 | 3篇 |
1942年 | 3篇 |
1917年 | 3篇 |
排序方式: 共有1081条查询结果,搜索用时 10 毫秒
91.
92.
Elisabeth Bodenstein Matthias Schober Marie Hoffmann Christoph Metzner Uwe Vogel 《Journal of the Society for Information Display》2018,26(9):555-560
We demonstrate the realization of red, green, and blue colors from top‐emitting white organic light‐emitting diode (OLED) for display applications. In our approach, red, green, and blue colors are realized by microcavity‐based mode selection from the spectrum of a white OLED. For the tuning of individual microcavities, the OLED hole transport layer is patterned by an electron beam process. 相似文献
93.
94.
George Bosilca Aurlien Bouteiller Elisabeth Brunet Franck Cappello Jack Dongarra Amina Guermouche Thomas Herault Yves Robert Frdric Vivien Dounia Zaidouni 《Concurrency and Computation》2014,26(17):2772-2791
In this paper, we present a unified model for several well‐known checkpoint/restart protocols. The proposed model is generic enough to encompass both extremes of the checkpoint/restart space, from coordinated approaches to a variety of uncoordinated checkpoint strategies (with message logging). We identify a set of crucial parameters, instantiate them, and compare the expected efficiency of the fault tolerant protocols, for a given application/platform pair. We then propose a detailed analysis of several scenarios, including some of the most powerful currently available high performance computing platforms, as well as anticipated Exascale designs. The results of this analytical comparison are corroborated by a comprehensive set of simulations. Altogether, they outline comparative behaviors of checkpoint strategies at very large scale, thereby providing insight that is hardly accessible to direct experimentation. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
95.
96.
Pieter Coenen Genevieve N. Healy Elisabeth A. H. Winkler David W. Dunstan Neville Owen Marj Moodie 《Ergonomics》2018,61(9):1187-1195
We examined the association of musculoskeletal symptoms (MSS) with workplace sitting, standing and stepping time, as well as sitting and standing time accumulation (i.e. usual bout duration of these activities), measured objectively with the activPAL3 monitor. Using baseline data from the Stand Up Victoria trial (216 office workers, 14 workplaces), cross-sectional associations of occupational activities with self-reported MSS (low-back, upper and lower extremity symptoms in the last three months) were examined using probit regression, correcting for clustering and adjusting for confounders. Sitting bout duration was significantly (p < 0.05) associated, non-linearly, with MSS, such that those in the middle tertile displayed the highest prevalence of upper extremity symptoms. Other associations were non-significant but sometimes involved large differences in symptom prevalence (e.g. 38%) by activity. Though causation is unclear, these non-linear associations suggest that sitting and its alternatives (i.e. standing and stepping) interact with MSS and this should be considered when designing safe work systems.
Practitioner summary: We studied associations of objectively assessed occupational activities with musculoskeletal symptoms in office workers. Workers who accumulated longer sitting bouts reported fewer upper extremity symptoms. Total activity duration was not significantly associated with musculoskeletal symptoms. We underline the importance of considering total volumes and patterns of activity time in musculoskeletal research. 相似文献
97.
Behavioral simulation is presented as a means to obtain complex global motion by simulating simple rules of behavior between locally related actors. A test-bed which has been developed to support experimentation with behavioral simulation is described. This test-bed has been used to create a library of physically behaving actors which can realistically reproduce the motion of flexible objects. The application of behavioral simulation to problems of motion specification in animation are described. The extension of this technique to simulate social behaviors is discussed. 相似文献
98.
Elisabeth Altmaier Gabi Kastenmüller Werner Römisch‐Margl Barbara Thorand Klaus M. Weinberger Jerzy Adamski Thomas Illig Angela Döring Karsten Suhre 《Molecular nutrition & food research》2009,53(11):1357-1365
The effect of coffee consumption on human health is still discussed controversially. Here, we report results from a metabolomics study of coffee consumption, where we measured 363 metabolites in blood serum of 284 male participants of the Cooperative Health Research in the Region of Augsburg study population, aged between 55 and 79 years. A statistical analysis of the association of metabolite concentrations and the number of cups of coffee consumed per day showed that coffee intake is positively associated with two classes of sphingomyelins, one containing a hydroxy‐group (SM(OH)) and the other having an additional carboxy‐group (SM(OH,COOH)). In contrast, long‐ and medium‐chain acylcarnitines were found to decrease with increasing coffee consumption. It is noteworthy that the concentration of total cholesterol also rises with an increased coffee intake in this study group. The association observed here between these hydroxylated and carboxylated sphingolipid species and coffee intake may be induced by changes in the cholesterol levels. Alternatively, these molecules may act as scavengers of oxidative species, which decrease with higher coffee intake. In summary, we demonstrate strong positive associations between coffee consumption and two classes of sphingomyelins and a negative association between coffee consumption and long‐ and medium‐chain acylcarnitines. 相似文献
99.
100.