全文获取类型
收费全文 | 3498篇 |
免费 | 201篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 51篇 |
综合类 | 3篇 |
化学工业 | 977篇 |
金属工艺 | 76篇 |
机械仪表 | 86篇 |
建筑科学 | 138篇 |
矿业工程 | 6篇 |
能源动力 | 160篇 |
轻工业 | 266篇 |
水利工程 | 28篇 |
石油天然气 | 3篇 |
无线电 | 353篇 |
一般工业技术 | 697篇 |
冶金工业 | 177篇 |
原子能技术 | 32篇 |
自动化技术 | 652篇 |
出版年
2023年 | 25篇 |
2022年 | 78篇 |
2021年 | 104篇 |
2020年 | 55篇 |
2019年 | 76篇 |
2018年 | 86篇 |
2017年 | 91篇 |
2016年 | 120篇 |
2015年 | 104篇 |
2014年 | 144篇 |
2013年 | 241篇 |
2012年 | 220篇 |
2011年 | 284篇 |
2010年 | 183篇 |
2009年 | 217篇 |
2008年 | 227篇 |
2007年 | 168篇 |
2006年 | 180篇 |
2005年 | 124篇 |
2004年 | 107篇 |
2003年 | 103篇 |
2002年 | 120篇 |
2001年 | 55篇 |
2000年 | 51篇 |
1999年 | 49篇 |
1998年 | 66篇 |
1997年 | 70篇 |
1996年 | 40篇 |
1995年 | 32篇 |
1994年 | 36篇 |
1993年 | 26篇 |
1992年 | 17篇 |
1991年 | 15篇 |
1990年 | 20篇 |
1989年 | 17篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 13篇 |
1985年 | 15篇 |
1984年 | 17篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 14篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 5篇 |
1972年 | 4篇 |
排序方式: 共有3705条查询结果,搜索用时 15 毫秒
991.
Zine Derhoumi Philippe Mandin Hervé Roustan Rolf Wüthrich 《Journal of Applied Electrochemistry》2013,43(12):1145-1161
During two-phase electrolysis, bubble production occurs at one or two electrodes. This yields a large change for the electrolyser electrical and hydrodynamic properties. Under normal Earth gravity, the bubble production at the electrodes induces a macro-convection in the electrolyser. This leads to a modified local current density distribution at the electrodes. When gravity is avoided, bubbles are no longer subject to buoyancy forces and to the induced natural flow friction forces. Electrolysis was performed using a potentiostat, and gas bubble evolution was observed with cameras. Quantitative evolution laws for the electrochemical cell voltage, bubble diameter and population during two-phase electrolysis are established in function of the current density and gravity variation. 相似文献
992.
Aberrant expression of glycosphingolipids is a hallmark of cancer cells and is associated with their malignant properties. Disialylated gangliosides GD2 and GD3 are considered as markers of neuroectoderm origin in tumors, whereas fucosyl-GM1 is expressed in very few normal tissues but overexpressed in a variety of cancers, especially in small cell lung carcinoma. These gangliosides are absent in most normal adult tissues, making them targets of interest in immuno-oncology. Passive and active immunotherapy strategies have been developed, and have shown promising results in clinical trials. In this review, we summarized the current knowledge on GD2, GD3, and fucosyl-GM1 expression in health and cancer, their biosynthesis pathways in the Golgi apparatus, and their biological roles. We described how their overexpression can affect intracellular signaling pathways, increasing the malignant phenotypes of cancer cells, including their metastatic potential and invasiveness. Finally, the different strategies used to target these tumor-associated gangliosides for immunotherapy were discussed, including the use and development of monoclonal antibodies, vaccines, immune system modulators, and immune effector-cell therapy, with a special focus on adoptive cellular therapy with T cells engineered to express chimeric antigen receptors. 相似文献
993.
994.
Hamza Hajjaji Sergey Alekseev Gérard Guillot Nicholas P Blanchard Virginie Monnier Yann Chevolot Georges Brémond Michel Querry David Philippon Philippe Vergne Jean Marie Bluet 《Nanoscale research letters》2014,9(1):94
Silicon nanoparticles (Si NPs) with a diameter size ranging from 4 to 8 nm were successfully fabricated. They exhibit a visible photoluminescence (PL) due to the quantum confinement effect. Chemical functionalization of these Si NPs with alkyl groups allowed to homogeneously disperse them in nonpolar liquids (NPLs). In comparison to most of literature results for Si NPs, an important PL peak position variation with temperature (almost 1 meV/K) was obtained from 303 to 390 K. The influence of the liquid viscosity on the peak positions is also presented. These variations are discussed considering energy transfer between nanoparticles. The high PL thermal sensitivity of the alkyl-capped Si NPs paves the way for their future application as nanothermometers. 相似文献
995.
Masakazu Ito Sylvain Lespinats Jens Merten Philippe Malbranche Kosuke Kurokawa 《Progress in Photovoltaics: Research and Applications》2016,24(2):159-174
Although the Sahara region has a high potential for solar power plants, the amount of installed photovoltaic (PV) system remains relatively low. This paper aims to evaluate these potentials of PV system installation in terms of environmental and economic viewpoints with indices of cost, energy, and greenhouse gas (GHG) emission. Two 1‐GW very large‐scale PV systems are simulated at Ouarzazate in Morocco and at Carpentras in France. The evaluation was performed using life cycle assessment. The lowest energy consumption and GHG emission are obtained while assuming cadmium telluride module. The result of our simulation shows that energy payback time is 0.9 years and CO2 emission rate is 27.4 g‐CO2‐eq/kWh in the Ouarzazate case. In cost estimation, generation costs are 0.06 USD/kWh in Ouarzazate and 0.09 USD/kWh in Carpentras in the case of 3% interest rate and 0.5 USD/W for multicrystalline silicon PV module price. In addition, by adapting 15% internal rate of return for 20% of budget, the generation costs become 0.09 USD/kWh in Ouarzazate and 0.13 USD/kWh in Carpentras under the same condition. Furthermore, the selection for suitable locations to install solar power plants in term of GHG emission is identified using geographical information system. Very high‐potential locations (lower than 38 g‐CO2‐eq/kWh) could be obtained in North Chili, east and west Sahara, and Mexico. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
996.
Nano-Micro Letters - A facile and rapid method to synthesize graphene/layered double hydroxide (LDH) nanohybrids by a microwave technique is demonstrated. The synthesis procedure involves... 相似文献
997.
Toughening of poly(lactide) using polyethylene glycol methyl ether acrylate: Reactive versus physical blending 下载免费PDF全文
Georgio Kfoury Jean‐Marie Raquez Fatima Hassouna Philippe Leclère Valérie Toniazzo David Ruch Philippe Dubois 《Polymer Engineering and Science》2015,55(6):1408-1419
To design high‐performance poly(lactide)‐based materials (PLA‐based) with improved toughness, two approaches based on the reactive extrusion (REx) process are investigated and compared in the present study. The first approach relies upon a two‐step procedure using a REx‐polymerized poly(ethylene glycol) methyl ether acrylate, i.e., poly(AcrylPEG), as a highly‐branched and compatible impact modifier for PLA. The free‐radical polymerization proves to be very efficient with a peroxide initiator concentration of 1 wt%. The as‐produced poly(AcrylPEG) is then melt‐blended with PLA by extrusion. The resulting materials exhibit largely increase impact resistance (ca. 35 kJ/m2) in presence of 20 wt% poly(AcrylPEG) in comparison with neat PLA (2.7 kJ/m2), while moderate ductility (tensile elongation at break <40%) and limited plasticization effect are observed. The second “one‐step” approach consists in in situ grafting of AcrylPEG onto PLA backbone via a one‐stage REx. The resulting materials exhibit substantially improved impact resistance (ca. 102 kJ/m2) for AcrylPEG loading of 20 wt%, high ductility (tensile elongation at break of ca. 150%) and efficient plasticization. A detailed characterization of the morphology of the materials has been performed using PF‐QNM‐AFM to better elucidate the structure‐property relationships. POLYM. ENG. SCI., 55:1408–1419, 2015. © 2015 Society of Plastics Engineers 相似文献
998.
999.
Ciprian Teodorov Luka Le Roux Zo Drey Philippe Dhaussy 《Software Testing, Verification and Reliability》2016,26(7):516-542
Model‐checking enables the automated formal verification of software systems through the explicit enumeration of all the reachable states. While this technique has been successfully applied to industrial systems, it suffers from the state‐space explosion problem because of the exponential growth in the number of states with respect to the number of interacting components. In this paper, we present a new reachability analysis algorithm, named Past‐Free[ze], that reduces the state‐space explosion problem by freeing parts of the state‐space from memory. This algorithm relies on the explicit isolation of the acyclic parts of the system before analysis. The parallel composition of these parts drives the reachability analysis, the core of all model‐checkers. During the execution, the past states of the system are freed from memory making room for more future states. To enable counter‐example construction, the past states can be stored on external storage. To show the effectiveness of the approach, the algorithm was implemented in the OBP Observation Engine and was evaluated both on a synthetic benchmark and on realistic case studies from automotive and aerospace domains. The benchmark, composed of 50 test cases, shows that in average, 75% of the state‐space can be dropped from memory thus enabling the exploration of up to 14 times more states than traditional approaches. Moreover, in some cases, the reachability analysis time can be reduced by up to 25%. In realistic settings, the use of Past‐Free[ze] enabled the exploration of a state‐space 4.5 times larger on the automotive case study, where almost 50% of the states are freed from memory. Moreover, this approach offers the possibility of analyzing an arbitrary number of interactions between the environment and the system‐under‐verification; for instance, in the case of the aerospace example, 1000 pilot/system interactions could be analyzed unraveling an 80 GB state‐space using only 10 GB of memory. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
1000.
The microstructural analysis of 1,4-cis- and of 1,4-trans-polymyrcene was conducted by means of thorough investigations at a very high field NMR (21.1T, 900 MHz). A set of 1D and 2D experiments helped to entirely assign the resonances of the spectra for both stereoisomers. A simple method to distinguish between each stereoisomer by NMR spectroscopy is finally provided. 相似文献