全文获取类型
收费全文 | 949篇 |
免费 | 51篇 |
专业分类
电工技术 | 22篇 |
综合类 | 1篇 |
化学工业 | 209篇 |
金属工艺 | 10篇 |
机械仪表 | 21篇 |
建筑科学 | 27篇 |
矿业工程 | 1篇 |
能源动力 | 21篇 |
轻工业 | 127篇 |
水利工程 | 7篇 |
石油天然气 | 3篇 |
无线电 | 47篇 |
一般工业技术 | 126篇 |
冶金工业 | 215篇 |
原子能技术 | 11篇 |
自动化技术 | 152篇 |
出版年
2023年 | 8篇 |
2022年 | 5篇 |
2021年 | 46篇 |
2020年 | 32篇 |
2019年 | 19篇 |
2018年 | 43篇 |
2017年 | 35篇 |
2016年 | 40篇 |
2015年 | 39篇 |
2014年 | 35篇 |
2013年 | 62篇 |
2012年 | 47篇 |
2011年 | 53篇 |
2010年 | 33篇 |
2009年 | 33篇 |
2008年 | 36篇 |
2007年 | 41篇 |
2006年 | 23篇 |
2005年 | 18篇 |
2004年 | 18篇 |
2003年 | 10篇 |
2002年 | 16篇 |
2001年 | 18篇 |
2000年 | 3篇 |
1999年 | 12篇 |
1998年 | 84篇 |
1997年 | 48篇 |
1996年 | 28篇 |
1995年 | 20篇 |
1994年 | 15篇 |
1993年 | 18篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1000条查询结果,搜索用时 187 毫秒
1.
Stefano Mariani Antonino Amedeo La Mattina Alessandro Paghi Lucanos Strambini Giuseppe Barillaro 《Advanced functional materials》2021,31(26):2100774
Here, a fluoride-assisted route for the controlled in-situ synthesis of metal nanoparticles (NPs) (i.e., AgNPs, AuNPs) on polydimethylsiloxane (PDMS) is reported. The size and coverage of the NPs on the PDMS surface are modulated with time and over space during the synthetic process, leveraging the improved yield (10×) and faster kinetics (100×) of NP formation in the presence of F− ions, compared to fluoride-free approaches. This enables the maskless preparation of both linear and step gradients and patterns of NPs in 1D and 2D on the PDMS surface. As an application in flexible plasmonics/photonics, continuous and step-wise spatial modulations of the plasmonic features of PDMS slabs with 1D and 2D AgNP gradients on the surface are demonstrated. An excellent spatially resolved tuning of key optical parameters, namely, optical density from zero to 5 and extinction ratio up to 100 dB, is achieved with AgNP gradients prepared in AgF solution for 12 minutes; the performance are comparable to those of commercial dielectric/interference filters. When used as a rejection filter in optical fluorescence microscopy, the AgNP-PDMS slabs are able to reject the excitation laser at 405 nm and retain the green fluorescence of microbeads (100 µm) used as test cases. 相似文献
2.
3.
Gina Cavaliere Giovanna Trinchese Nadia Musco Federico Infascelli Chiara De Filippo Vincenzo Mastellone Valeria Maria Morittu Pietro Lombardi Raffaella Tudisco Micaela Grossi Vincenzo Monda Monica I. Cutrignelli Antonietta Messina Serena Calabrò Heleena B. Moni Luigi Stradella Giovanni Messina Marcellino Monda Maria Pina Mollica 《Journal of dairy science》2018,101(3):1843-1851
Excessive energy intake may evoke complex biochemical processes characterized by inflammation, oxidative stress, and impairment of mitochondrial function that represent the main factors underlying noncommunicable diseases. Because cow milk is widely used for human nutrition and in food industry processing, the nutritional quality of milk is of special interest with respect to human health. In our study, we analyzed milk produced by dairy cows fed a diet characterized by a high forage:concentrate ratio (high forage milk, HFM). In view of the low n-6:n-3 ratio and high content of conjugated linoleic acid of HFM, we studied the effects of this milk on lipid metabolism, inflammation, mitochondrial function, and oxidative stress in a rat model. To this end, we supplemented for 4 wk the diet of male Wistar rats with HFM and with an isocaloric amount (82 kJ, 22 mL/d) of milk obtained from cows fed a diet with low forage:concentrate ratio, and analyzed the metabolic parameters of the animals. Our results indicate that HFM may positively affect lipid metabolism, leptin:adiponectin ratio, inflammation, mitochondrial function, and oxidative stress, providing the first evidence of the beneficial effects of HFM on rat metabolism. 相似文献
4.
Colzato Lorenza S.; Raffone Antonino; Hommel Bernhard 《Canadian Metallurgical Quarterly》2006,32(3):705
Four experiments were conducted to investigate the relationship between the binding of visual features (as measured by their aftereffects on subsequent binding) and the learning of feature-conjunction probabilities. Both binding and learning effects were obtained, but they did not interact. Interestingly, (shape-color) binding effects disappeared with increasing practice, presumably because of the fact that only 1 of the features involved was relevant to the task. However, this instability was only observed for arbitrary, not highly overlearned combinations of simple geometric features and not for real objects (colored pictures of a banana and strawberry), where binding effects were strong and resistant to practice. These findings suggest that learning has no direct impact on the strength or resistance of bindings or on speed with which features are bound; however, learning does affect the amount of attention particular feature dimensions attract, which again can influence which features are considered in binding. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
5.
We have analyzed the compositional properties of coding (protein encoding) and non-coding sequences of Plasmodium falciparum, a unicellular parasite characterized by an extremely AT-rich genome. GC% levels, base and dinucleotide frequencies were studied. We found that among the various factors that contribute to the properties of the sequences analyzed, the most relevant are the compositional constraints which operate on the whole genome. 相似文献
6.
7.
8.
Fabrizo Granelli Honggang Zhang Xiaofei Zhou Stefano Maranò 《Mobile Networks and Applications》2006,11(4):487-499
The paper illustrates the novel concept of Cognitive UWB Radio, a wireless system based on UWB transmission able to self-adapt to the characteristics of the surrounding environment. First, salient features of UWB transmission are reviewed, and then, application of UWB characteristics to the problem of cognitive radio systems is discussed. Current ongoing studies and achieved results on a possible physical layer based on Prolate Spheroidal Wave Functions and consistent with the Cognitive UWB Radio paradigm are presented and analyzed, and their application to the sensor network scenario is discussed. 相似文献
9.
D. P. Dreoni D. Pinelli F. Trifirò Z. Tvaruzkova H. Habersberger P. Jiru 《Catalysis Letters》1991,11(3-6):285-294
The catalyst behaviour of titanium silicalite, which was found the most active and selective catalyst for liquid-phase ammoximation of cyclohexanone to the corresponding oxime with hydrogen peroxide, was investigated in the gas-phase ammoximation with molecular oxygen in and compared with those of pure silicalite and samples of vanadium and chromium silicalites. The results showed that Ti-silicalite is a selective catalyst not only in the reaction with hydrogen peroxide but also in the reaction with molecular oxygen. However, a big limitation was found in the poor activity of the silicalites which do not allow to reach high oxime yields. 相似文献
10.
OBJECTIVE: To analyze the short- and medium-term results of the Burch-like urethropexy with bone anchors in the treatment of genuine stress urinary incontinence. METHODS: We performed the conventional Burch technique which was modified with the use of 4 bone anchors for bony fixation. Forty-four female patients with genuine stress urinary incontinence were operated on from November, 1995 to November, 1997. RESULTS: The patients had a bladder catheter indwelling for 4 to 9 days and only 3 of them required intermittent catheterization during two months. All patients recovered spontaneous micturition. The postoperative urinary continence was 93% at a mean follow-up of 11 months. CONCLUSIONS: Although our initial results seem encouraging, a continuous and objective follow-up is warranted to assess the long-term efficacy of this technique. 相似文献