全文获取类型
收费全文 | 560篇 |
免费 | 29篇 |
学科分类
工业技术 | 589篇 |
出版年
2023年 | 7篇 |
2022年 | 41篇 |
2021年 | 33篇 |
2020年 | 15篇 |
2019年 | 17篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 18篇 |
2015年 | 23篇 |
2014年 | 23篇 |
2013年 | 42篇 |
2012年 | 40篇 |
2011年 | 28篇 |
2010年 | 23篇 |
2009年 | 25篇 |
2008年 | 12篇 |
2007年 | 33篇 |
2006年 | 20篇 |
2005年 | 13篇 |
2004年 | 16篇 |
2003年 | 17篇 |
2002年 | 12篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 10篇 |
1998年 | 17篇 |
1997年 | 17篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有589条查询结果,搜索用时 15 毫秒
191.
192.
Roberge Pasquale; Marchand André; Reinharz Daniel; Marchand Lyne; Cloutier Karine 《Canadian Metallurgical Quarterly》2004,45(3):202
This literature review examines the results of cost-effectiveness studies of cognitive-behaviour therapies published up to June 2003. Cost offsets likely to be derived from effective treatment of anxiety problems are also examined. A summary of results suggests the following: 1) cognitive-behaviour therapy is cost-effective compared to drug therapy for the treatment of panic disorder and social phobia; 2) group treatments and short courses as well as new technologies are promising alternatives to conventional therapy; 3) the existence of cost offsets for anxiety disorders has yet to be ascertained. Research approaches are suggested to cover significant shortcomings in the methodologies of studies conducted to date. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
193.
We investigate the entanglement properties of the Kondo spin chain when it is prepared in its ground state as well as its
dynamics following a single bond quench. We show that a true measure of entanglement such as negativity enables to characterize
the unique features of the gapless Kondo regime. We determine the spatial extent of the Kondo screening cloud and propose
an ansatz for the ground state in the Kondo regime accessible to this spin chain; we also demonstrate that the impurity spin
is indeed maximally entangled with the Kondo cloud. We exploit these features of the entanglement in the gapless Kondo regime
to show that a single local quench at one end of a Kondo spin chain may always induce a fast and long lived oscillatory dynamics,
which establishes a high quality entanglement between the individual spins at the opposite ends of the chain. This entanglement
is a footprint of the presence of the Kondo cloud and may be engineered so as to attain—even for very large chains—a constant
high value independent of the length; in addition, it is thermally robust. Moreover, we show that high entanglement between
very distant boundary spins is generated by suddenly connecting two long Kondo spin chains. We show that this procedure provides
an efficient way to route entanglement between multiple distant sites. To better evidence the remarkable peculiarities of
the Kondo regime, we carry a parallel analysis of the entanglement properties of the Kondo spin chain model in the gapped
dimerised regime where these remarkable features are absent. 相似文献
194.
Gabriele Giro Massimo Cocchi Jan Kalinowski Valeria Fattori Piergiulio Di Marco Pasquale Dembech Giancarlo Seconi 《Advanced functional materials》1999,9(5):189-194
A new diamine, N,N′-diphenyl-N,N′-bis-biphenyl-(1,1′-biphenyl)-4,4′-diamine (PTPD), has been synthesised to be applied as a hole-transporting material for multilayer organic light-emitting diodes (LEDs). Electrical and optical characteristics of a series of double-layer (DL) LEDs using PTPD as hole-transporting layers (HTL) and Alq3 and Znq2 as electron-transporting layers have been measured and compared with those for DL LEDs based on other HTLs (TPD and NTPD). The differences are discussed in terms of charge injection at the electrodes and electron–hole recombination processes at the organic interfaces. The prerequisites based on the molecular structure of the compound, confirmed by preliminary experimental observations, suggest PTPD to be a stable hole-transporting material for high-durability organic LEDs. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
195.
Integrating analog-to-digital converters (IADCs) basically include an analog signal processing section for conditioning and integrating the input signal, and a quantizing section for obtaining the digital converted signal. The main dynamic errors arise from the analog signal processing section. In this paper, the resulting dynamic integral nonlinearity of IADCs is analytically derived and a model based on a low-order polynomial function of the input signal slope and the output code is proposed. The analytical model is useful for reducing experimental burden related to dynamic metrological characterisation. Experimental validation results highlight the model effectiveness in describing integral nonlinearity of an actual dual-slope IADC. 相似文献
196.
In recent years, several studies have examined the multifaceted role of mitochondria in Multiple Sclerosis (MS), suggesting that, besides inflammation and demyelination, mitochondrial aberration is a crucial factor in mediating axonal degeneration, the latter being responsible for persistent disabilities in MS patients. Therefore, mitochondria have been recognized as a possible multiple sclerosis therapeutic target. Recently, mitochondrial transplantation has become a new term for the transfer of live mitochondria into damaged cells for the treatment of various diseases, including neurodegenerative diseases. In this hypothesis, we propose mitochondrial transplantation as a new, potentially applicable approach to counteract axonal degeneration in multiple sclerosis. 相似文献
197.
Giuliana Gorrasi Stéphane Bredeau Chiara Di Candia Giovanni Patimo Salvatore De Pasquale Philippe Dubois 《大分子材料与工程》2011,296(5):408-413
Preparation and analysis of morphologic and electrical properties of high‐performance multiwalled carbon nanotube/polyamide 6 nanocomposites was achieved. The MWNTs were surface‐coated by in situ polymerization of ethylene as catalyzed directly from the nanotube surface previously treated by a highly active metallocene‐based complex. The so‐produced polyethylene‐coated MWNTs were melt‐mixed with the PA6 matrix. Pristine MWNTs were also dispersed in PA6. The in situ ethylene polymerization/coating reaction allowed the destructuring of the native bundle‐like aggregates leading to the preparation of nanocomposites with improved properties even at very low nanofiller content.
198.
In the preparation of polymer/montmorillonite (MMT) nanocomposites, the commonly used compatibilizers (cations of long carbon‐chain alkyl ammonium salts) present the drawback of a poor thermal stability. During bulk processing of nanocomposites elevated temperatures are usually required and, if processing temperature is close to decomposition temperature of the surfactant, decomposition will occur altering the interface between filler and polymer. To solve this problem, organically modified MMTs with thermally stable imidazolium surfactants have been prepared. A series of nanocomposites were obtained by dispersing o‐MMT in poly(methyl methacryate) (PMMA) matrix via an in situ free radical polymerization. The nanocomposites were characterized by X‐ray diffraction, transmission electron microscopy, gel permeation chromatography, thermogravimetric analysis, dynamic mechanical analysis, and nanoindentation measurements. The results showed that nanocomposite thermal stability depended on both the kind of used surfactant and degree of exfoliation. Under the same values of molecular weight, the nanocomposites containing imidazolium cations showed a better thermal stability with respect to the nanocomposite obtained using a standard alkylammonium surfactant. Dynamic mechanical and Nanoindentation measurements showed an improvement of mechanical properties, such as modulus and hardness, with respect to pure PMMA. Solution blending treatments on these nanocomposites led to obtaining of further improvement of the thermal performance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41393. 相似文献
199.
200.
约瑟夫:米兰作为2015年世博会主办城市,您认为世博会能为米兰提供什么机会?特别是城市管理方面,政府有什么预期目标? 卡罗:米兰世博会体现了正面的发展,我们应该遵循米兰精神:在接近城市的传统和渊源的同时与国际接轨. 相似文献