全文获取类型
收费全文 | 554篇 |
免费 | 46篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 144篇 |
金属工艺 | 13篇 |
机械仪表 | 4篇 |
建筑科学 | 14篇 |
能源动力 | 13篇 |
轻工业 | 69篇 |
水利工程 | 3篇 |
无线电 | 58篇 |
一般工业技术 | 121篇 |
冶金工业 | 78篇 |
原子能技术 | 6篇 |
自动化技术 | 68篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 11篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 12篇 |
2017年 | 16篇 |
2016年 | 12篇 |
2015年 | 25篇 |
2014年 | 34篇 |
2013年 | 37篇 |
2012年 | 33篇 |
2011年 | 44篇 |
2010年 | 22篇 |
2009年 | 30篇 |
2008年 | 21篇 |
2007年 | 34篇 |
2006年 | 22篇 |
2005年 | 19篇 |
2004年 | 14篇 |
2003年 | 15篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 3篇 |
1998年 | 30篇 |
1997年 | 25篇 |
1996年 | 11篇 |
1995年 | 14篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1987年 | 7篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 4篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有600条查询结果,搜索用时 234 毫秒
91.
Field Bus applications 总被引:1,自引:0,他引:1
Richard H. Caro 《ISA transactions》1989,28(4):65-70
The ISA-SP550 Field Bus draft standard offers new opportunities to configure multivendor systems for a variety of applications never before possible with distributed control systems. It is not yet clear how vendors will respond with new types of products, but users of process control equipment will be sure to benefit as the conventional functions of measurement, control, display, and actuations become interchangeable commodity products. Not only does the Field Bus draft standard normalize data communications at practical and cost-effective levels, but for the first time the functions of process control become defined with common terminology and interfaces. The mystery has been removed, freeing the user to concentrate on solving the process problems rather than the instrumentation problems. This paper presents the details of the process control applications layer standard so that users may begin to understand how to apply Field Bus solutions to common process control problems. 相似文献
92.
Pau Bitlloch Xavier Ruiz Laureano Ramírez-Piscina Jaume Casademunt 《Microgravity science and technology》2018,30(4):525-534
Lattice-Boltzmann simulations of a turbulent duct flow have been carried out to obtain trajectories of passive tracers in the conditions of a series of microgravity experiments of turbulent bubble suspensions. The statistics of these passive tracers are compared to the corresponding measurements for single-bubble and bubble-pair statistics obtained from particle tracking techniques after the high-speed camera recordings from drop-towers experiments. In the conditions of the present experiments, comparisons indicate that experimental results on bubble velocity fluctuations are not consistent with simulations of passive tracers, which points in the direction of an active role of bubbles. The present analysis illustrates the utility of a recently introduced experimental setup to generate controlled turbulent bubble suspensions in microgravity. 相似文献
93.
Davide Blasi Nerea Gonzalez-Pato Xavier Rodriguez Rodriguez Iñigo Diez-Zabala Sumithra Yasaswini Srinivasan Núria Camarero Oriol Esquivias Mònica Roldán Judith Guasch Anna Laromaine Pau Gorostiza Jaume Veciana Imma Ratera 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(32):2370250
Ratiometric fluorescent nanothermometers with near-infrared emission play an important role in in vivo sensing since they can be used as intracellular thermal sensing probes with high spatial resolution and high sensitivity, to investigate cellular functions of interest in diagnosis and therapy, where current approaches are not effective. Herein, the temperature-dependent fluorescence of organic nanoparticles is designed, synthesized, and studied based on the dual emission, generated by monomer and excimer species, of the tris(2,4,6-trichlorophenyl)methyl radical (TTM) doping organic nanoparticles (TTMd-ONPs), made of optically neutral tris(2,4,6-trichlorophenyl)methane (TTM-αH), acting as a matrix. The excimer emission intensity of TTMd-ONPs decreases with increasing temperatures whereas the monomer emission is almost independent and can be used as an internal reference. TTMd-ONPs show a great temperature sensitivity (3.4% K−1 at 328 K) and a wide temperature response at ambient conditions with excellent reversibility and high colloidal stability. In addition, TTMd-ONPs are not cytotoxic and their ratiometric outputs are unaffected by changes in the environment. Individual TTMd-ONPs are able to sense temperature changes at the nano-microscale. In vivo thermometry experiments in Caenorhabditis elegans (C. elegans) worms show that TTMd-ONPs can locally monitor internal body temperature changes with spatio-temporal resolution and high sensitivity, offering multiple applications in the biological nanothermometry field. 相似文献
94.
Marianna Rossetti Lorenzo Stella Judit Morlà-Folch Sara Bobone Ariadna Boloix Lorena Baranda Danila Moscone Mònica Roldán Jaume Veciana Miguel F. Segura Mariana Köber Nora Ventosa Alessandro Porchetta 《Advanced functional materials》2021,31(46):2103511
The development of artificial vesicles into responsive architectures capable of sensing the biological environment and simultaneously signaling the presence of a specific target molecule is a key challenge in a range of biomedical applications from drug delivery to diagnostic tools. Herein, the rational design of biomimetic DNA-grafted quatsome (QS) nanovesicles capable of translating the binding of a target molecule to amphiphilic DNA probes into an optical output is presented. QSs are synthetic lipid-based nanovesicles able to confine multiple organic dyes at the nanoscale, resulting in ultra-bright soft materials with attractiveness for sensing applications. Dye-loaded QS nanovesicles of different composition and surface charge are grafted with fluorescent amphiphilic nucleic acid-based probes to produce programmable FRET-active nanovesicles that operate as highly sensitive signal transducers. The photophysical properties of the DNA-grafted nanovesicles are characterized and the highly selective, ratiometric detection of clinically relevant microRNAs with sensitivity in the low nanomolar range are demonstrated. The potential applications of responsive QS nanovesicles for biosensing applications but also as functional nanodevices for targeted biomedical applications is envisaged. 相似文献
95.
Fitó M Covas MI Lamuela-Raventós RM Vila J Torrents L de la Torre C Marrugat J 《Lipids》2000,35(6):633-638
The protective effect of phenolic compounds from an olive oil extract, and of olive oils with (extra-virgin) and without (refined)
phenolic components, on low density lipoprotein (LDL) oxidation was investigated. When added to isolated LDL, phenolics [0.025–0.3
mg/L caffeic acid equivalents (CAE)] increased the lag time of conjugated diene formation after copper-mediated LDL oxidation
in a concentration-dependent manner. Concentrations of phenolics greater than 20 mg/L inhibited formation of thiobarbituric-acid
reactive substances after AAPH-initiated LDL oxidation. LDL isolated from plasma after preincubation with phenolics (25–160
mg/L CAE) showed a concentration-dependent increase in the lag time of conjugated diene formation after copper-mediated LDL
oxidation. Refined olive oil (0 mg/L CAE) and extra-virgin olive oil (0.1 and 0.3 mg/L CAE) added to isolated LDL caused an
increase in the lag time of conjugated diene formation after copper-mediated LDL oxidation that was related to olive oil phenolic
content. Multiple regression analysis showed that phenolics were significantly associated with the increase in lag time after
adjustment for effects of other antioxidants; α-tocopherol also achieved a statistically significant effect. These results
indicate that olive oil phenolic compounds protect LDL against peroxyl radical-dependent and metal-induced oxidation in vitro and could associate with LDL after their incubation with plasma. Both types of olive oil protect LDL from oxidation. Olive
oil containing phenolics, however, shows more antioxidant effect on LDL oxidation than refined olive oil. 相似文献
96.
Pascale Satgé de Caro Zéphirin Mouloungui Antoine Gaset 《Journal of the American Oil Chemists' Society》1997,74(3):235-240
Alkyl glycidyl ethers and bis glycidyl ethers, synthesized in a heterogeneous weakly hydrous medium, were condensed with primary
or secondary amines to obtain 3-alkyloxy propanolamines or bis alkyloxy propanolamines in a regioselective manner. The compounds
were characterized by conventional spectroscopic methods, and complete nuclear magnetic resonance data are given. Their high-temperature
stability, their good emulsifying power, their oxidation, and corrosion inhibition make these compounds suitable for solubilizing
ethanol-diesel fuel blends. 相似文献
97.
Valorization of waste thermoset material as a filler in thermoplastic: Mechanical properties of phenolic molding compound waste‐filled PP composites
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Fabien Bernardeau Didier Perrin Anne‐Sophie Caro Jean‐Charles Benezet Patrick Ienny 《应用聚合物科学杂志》2018,135(12)
As most thermoset material, phenolic molding compound (PMC) wastes are an environmental problem. Very few recycling solutions have been proposed so far for this type of material. A mechanical recycling method to valorize these materials is proposed in this work. It relies on the use of phenolic waste as filler in thermoplastic. Such phenolic filler can increase mechanical properties (tensile, flexural) of the matrix, and be used in substitution of traditional particulate fillers such as calcium carbonate or talc. In this study, several morphological parameters influencing the final mechanical properties of a PMC‐filled polypropylene (PP) micro‐composite are studied, such as filler loading rate, particles size distribution of the filler, and interfacial adhesion between the filler and the matrix. Some structural parameters are also studied and linked with mechanical properties, such as dispersion of the filler and crystallinity of the matrix. Finally, the properties of PMC‐filled PP are compared with CaCO3‐ and talc‐filled PP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45849. 相似文献
98.
Fengqing?Liu Jaume?ComellasEmail authorView authors OrcID profile 《Photonic Network Communications》2017,33(3):334-347
A precise alignment between point-to-point free space optical (FSO) networks is crucial in order to maximize the performance of data transmission. A sway or low-frequency vibration of FSO base station can affect line-of-sight quality and hence may lead to the occurrence of higher BER. Therefore, the work presented in this paper is to demonstrate an improved auto-alignment single-channel FSO transmission system at X-axis detection area. The receiver base station was fed with pulsed signal laser from a tunable laser source with a central wavelength of 1550 nm. The detection mechanism responds from an analog input signal received that corresponds to the X-axis direction of transmitter vibration. The detection performance of the system was observed by using two approaches: auto-searching of artificial intelligence (AI) detection with stop command and without stop command. The obtained results indicate that the bit sequence of the pulsed signal has low loss by implementing the auto-searching of AI detection with stop command features and hence improves the efficiency of the overall FSO transmission system. 相似文献
99.
Arterial geometry is commonly non-planar and associated with swirling blood flow. In this study, we examine the effect of arterial three-dimensionality on the distribution of wall shear stress (WSS) and the mass transfer of oxygen from the blood to the vessel wall in a U-bend, by modelling the blood vessels as either cylindrical or helical conduits. The results show that under physiological flow conditions, three-dimensionality can reduce both the range and extent of low WSS regions and substantially increase oxygen flux through the walls. The Sherwood number and WSS distributions between the three-dimensional helical model and a human coronary artery show remarkable qualitative agreement, implying that coronary arteries may potentially be described with a relatively simple idealized three-dimensional model, characterized by a small number of well-defined geometric parameters. The flow pattern downstream of a planar bend results in separation of the Sh number and WSS effects, a finding that implies means of investigating them individually. 相似文献
100.
Molecular Sieve Membranes for Industrial Applications – Problems, Advances, Solutions Molecular sieve membranes are characterised by their high thermal and chemical resistance and by their monodisperse micropore system. Mixtures can be separated according to molecular size as well as according to adsorptive interactions and diffusion differences. This paper outlines techniques for reproducible production of large area membranes together with methods for their regeneration and repair. Typical separations demonstrate the efficiency of these membranes. Potential application fields can be deduced from developmental trends. 相似文献