全文获取类型
收费全文 | 1788篇 |
免费 | 174篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 8篇 |
综合类 | 4篇 |
化学工业 | 775篇 |
金属工艺 | 17篇 |
机械仪表 | 35篇 |
建筑科学 | 47篇 |
矿业工程 | 4篇 |
能源动力 | 40篇 |
轻工业 | 356篇 |
水利工程 | 12篇 |
石油天然气 | 9篇 |
无线电 | 90篇 |
一般工业技术 | 265篇 |
冶金工业 | 49篇 |
原子能技术 | 3篇 |
自动化技术 | 249篇 |
出版年
2024年 | 8篇 |
2023年 | 19篇 |
2022年 | 124篇 |
2021年 | 199篇 |
2020年 | 60篇 |
2019年 | 76篇 |
2018年 | 67篇 |
2017年 | 79篇 |
2016年 | 100篇 |
2015年 | 85篇 |
2014年 | 95篇 |
2013年 | 139篇 |
2012年 | 128篇 |
2011年 | 133篇 |
2010年 | 95篇 |
2009年 | 102篇 |
2008年 | 103篇 |
2007年 | 65篇 |
2006年 | 63篇 |
2005年 | 56篇 |
2004年 | 34篇 |
2003年 | 28篇 |
2002年 | 20篇 |
2001年 | 17篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有1963条查询结果,搜索用时 562 毫秒
111.
In this paper, we develop self-assembling robot systems composed of active modular robots and passive bars. The target structure is modeled as a dynamic graph. We present two provably correct algorithms for creating the structure. A decentralized optimal algorithm for the navigation of multiple modular robots on a partial truss structure is used to guide the robots to their location on the target structure. A decentralized algorithm for scheduling the transportation and placement of truss elements is used to coordinate the creation of the target structure. Both algorithms rely on locally optimal matching. The truss self-assembly algorithm has quadratic competitive ratio for static as well as dynamic graph representation. We show simulation results and results for experiments with two 3DOF robots and passive bars that can create and control a 6DOF manipulation. 相似文献
112.
Davis Castro dos Santos Matthew Ayorinde Adebayo Simone de Fátima Pinheiro Pereira Lizie Daniela Tentler Prola Renato Cataluña Eder Cláudio Lima Caroline Saucier Caline Rodrigues Gally Fernando Machado Machado 《Korean Journal of Chemical Engineering》2014,31(8):1470-1479
New carbon composite materials were prepared by pyrolysis of mixture of coffee wastes and red mud at 700 °C with the inorganic: organic ratios of 1.9 (CC-1.9) and 2.2 (CC-2.2). These adsorbents were used to remove reactive orange 16 (RO-16) and reactive red 120 (RR-120) textile dyes from aqueous solution. The CC-1.9 and CC-2.2 materials were characterized using Fourier transform infrared spectroscopy, Nitrogen adsorption/desorption curves, scanning electron Microscopy and X-ray diffraction. The kinetic of adsorption data was fitted by general order kinetic model. A three-parameter isotherm model, Liu isotherm model, gave the best fit of the equilibrium data (298 to 323 K). The maximum amounts of dyes removed at 323 K were 144.8 (CC-1.9) and 139.5 mg g?1 (CC-2.2) for RO-16 dye and 95.76 (CC-1.9) and 93.80 mg g?1 (CC-2.2) for RR-120 dye. Two simulated dyehouse effluents were used to investigate the application of the adsorbents for effluent treatment. 相似文献
113.
The study investigates the effects of the roughness of the metal counterface (mirror finished or polished) on the coefficient of dry friction for some of the most common engineering plastics used in current bearing technology. The results show that an optimal roughness for minimum friction is likely to exist for any polymer, and it depends on the bulk properties of the polymer itself. “Soft” plastics characterized by a low modulus of elasticity exhibit better sliding behaviour on very smooth, mirror finished surfaces, whereas for high-modulus plastics lower friction is measured in combination with rougher, polished counterfaces. The influence of the contact pressure and sliding velocity are also investigated and found to depend on the layout of the tribological system. 相似文献
114.
This paper presents an electronic system for a fast DNA label-less detection. The sensitivity of the capacitive sensor in use is improved by depositing an insulating self-assembled monolayer (SAM) over the golden electrodes. The capacitance shift due to the hybridization effect is monitored by means of a charge-sensitive amplifier and digitalized by means of a comparator and a counter. The read-out solution demonstrates the ability to identify a 0.01% variation on the capacitive value of the sensor. Results from measurements with the optimized sensor show the reliability of the electronics. The investigated solution is suitable for monolithic systems or for a micro-fabricated array of sensors. An example of the integrated front-end is described and performances and noise evaluation are reported here. 相似文献
115.
Daniele Viciani Lorella Dell’Olmo Antonio Gabellini Daniela Gigante Lorenzo Lastrucci 《Landscape Research》2018,43(7):952-964
Widespread trends of abandonment have strongly affected Mediterranean mountains after the Second World War, triggering spontaneous recolonisation of forests. A diachronic analysis of the landscape in a Natura 2000 site (Tuscany, Italy) was carried out using digital aerial photographs (1954, 2013) and a GIS-based methodology, focusing on territories above 1300 m a.s.l. The detected variations of total areas, patch shape, patch dimensions and selected metrics showed a notable shift of the vegetation towards woody types and a drastic reduction of open grasslands, some with high conservation value, accompanied by a strong increase in patch number, surface and edge. A decrease of SDI and SEI diversity indices was also observed. Considering that fragmentation is one of the main causes threatening habitats and species, our results point out a clear necessity for a monitoring programme and suitable actions aimed at improving the status of biodiversity-rich montane grasslands. 相似文献
116.
Isabella Panfoli Daniela Calzia Silvia Ravera Paolo Bianchini Alberto Diaspro 《Microscopy research and technique》2010,73(12):1086-1090
We describe a procedure for the labeling of membranous vesicular purified subcellular fractions, to image them, typically by confocal laser scanning microscopy. Being intracellular organelles, these fractions, once purified cannot be attached to glass slides as for cells. Fractions are labeled “in batch” without prior embedding or freezing. Each labeling step performed by passages of resuspension/centrifugation is followed by washings. Then samples are dispersed on the glass slides. Mammalian retinal rod outer segment disks, intact brain stem myelin vesicles, and brain synaptosomes were chosen, as these subcellular fractions can be purified by well established procedures. These fractions were immunolabeled with specific antibodies. Moreover, by the earlier procedure, we show that the mitochondrial vital membrane potential probe MitoTracker Deep Red 633 stains myelin vesicles and rod disks before fixation, consistently with our previous reports of a respiring capacity of these membranes. Therefore, the technique seems adequate to become an instrument to study the structure and the function of these and other subcellular fractions. Microsc. Res. Tech. 73:1086–1090, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
117.
Daniela Erriquez Giovanni Perini Alessandra Ferlini 《International journal of molecular sciences》2013,14(10):19681-19704
ncRNAs are the most recently identified class of regulatory RNAs with vital functions in gene expression regulation and cell development. Among the variety of roles they play, their involvement in human diseases has opened new avenues of research towards the discovery and development of novel therapeutic approaches. Important data come from the field of hereditary muscle dystrophies, like Duchenne muscle dystrophy and Myotonic dystrophies, rare diseases affecting 1 in 7000–15,000 newborns and is characterized by severe to mild muscle weakness associated with cardiac involvement. Novel therapeutic approaches are now ongoing for these diseases, also based on splicing modulation. In this review we provide an overview about ncRNAs and their behavior in muscular dystrophy and explore their links with diagnosis, prognosis and treatments, highlighting the role of regulatory RNAs in these pathologies. 相似文献
118.
Daniela F. Olivera Viviana O. Salvadori 《International Journal of Food Science & Technology》2011,46(7):1445-1454
Food consumption patterns have changed significantly during the last years, showing an increase in the consumption of convenience foods. Frozen foods represent an important segment of this market. The aim of the present paper was to study the influence of frozen storage on the quality of cooked organic tagliatelle. Instrumental measurements of different quality parameters (moisture content, colour, textural and rheological characteristics of frozen cooked pasta) were performed during twelve months of storage. The sensory properties of pasta were also evaluated by means of an acceptability study. In general, both instrumental and sensory analysis found that frozen storage affects negatively the acceptability of cooked pasta. The advantages obtained through fast freezing procedures are not maintained along storage, being hardness (instrumental) and consistency (sensory) the most relevant quality indices. Finally, the shelf life of the product was calculated as 3.6 and 3.8 months in the cryogenic device and air‐blast tunnel, respectively, based on simple kinetic models. 相似文献
119.
Potentilla erecta (L.) is known for the high concentration of proanthocyanidin oligomers (PAs) in its underground parts. The use of its preparations as food supplements and the lack of chemical–analytical studies concerning with an efficient chromatographic separation procedure for these compounds led us to develop a strategy to profile PAs occurring in this species. 相似文献