全文获取类型
收费全文 | 6999篇 |
免费 | 461篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 67篇 |
综合类 | 1篇 |
化学工业 | 1810篇 |
金属工艺 | 179篇 |
机械仪表 | 173篇 |
建筑科学 | 274篇 |
矿业工程 | 25篇 |
能源动力 | 266篇 |
轻工业 | 950篇 |
水利工程 | 47篇 |
石油天然气 | 42篇 |
无线电 | 502篇 |
一般工业技术 | 1516篇 |
冶金工业 | 315篇 |
原子能技术 | 56篇 |
自动化技术 | 1242篇 |
出版年
2024年 | 31篇 |
2023年 | 71篇 |
2022年 | 119篇 |
2021年 | 219篇 |
2020年 | 208篇 |
2019年 | 183篇 |
2018年 | 303篇 |
2017年 | 330篇 |
2016年 | 382篇 |
2015年 | 230篇 |
2014年 | 329篇 |
2013年 | 676篇 |
2012年 | 386篇 |
2011年 | 517篇 |
2010年 | 388篇 |
2009年 | 410篇 |
2008年 | 367篇 |
2007年 | 333篇 |
2006年 | 268篇 |
2005年 | 195篇 |
2004年 | 179篇 |
2003年 | 156篇 |
2002年 | 150篇 |
2001年 | 83篇 |
2000年 | 88篇 |
1999年 | 77篇 |
1998年 | 94篇 |
1997年 | 82篇 |
1996年 | 71篇 |
1995年 | 51篇 |
1994年 | 51篇 |
1993年 | 40篇 |
1992年 | 36篇 |
1991年 | 32篇 |
1990年 | 20篇 |
1989年 | 22篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 15篇 |
1985年 | 29篇 |
1984年 | 12篇 |
1983年 | 12篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 12篇 |
1979年 | 15篇 |
1978年 | 14篇 |
1977年 | 15篇 |
1976年 | 14篇 |
1974年 | 11篇 |
排序方式: 共有7465条查询结果,搜索用时 15 毫秒
21.
Christophe Lombard Stephane Le Doze Eric Marencak Paul-Marie Marquaire David Le Noc Grégory Bertrand François Lapicque 《International Journal of Hydrogen Energy》2006
The paper reports the results of on-site regeneration catalytic bed of the natural gas reformer in a 5 kW PEM fuel cell system. The Ni catalyst previously poisoned by sulphur from the available natural gas, could be re-activated by injection of pure water steam, following the method developed for industrial reformers using the same metal catalyst: this method was shown to be perfectly efficient, provided no natural gas was fed during the operation. Results of the tests conducted are presented and discussed in relation to published data on S-sorption on Ni surfaces. 相似文献
22.
Sabri Boughorbel Jean-Philippe Tarel Fran?ois Fleuret Nozha Boujemaa 《The Journal of supercomputing》1988,2(4):449-450
Contributing authors 相似文献
23.
24.
We propose a method for non-uniform reconstruction of 3D scalar data. Typically, radial basis functions, trigonometric polynomials or shift-invariant functions are used in the functional approximation of 3D data. We adopt a variational approach for the reconstruction and rendering of 3D data. The principle idea is based on data fitting via thin-plate splines. An approximation by B-splines offers more compact support for fast reconstruction. We adopt this method for large datasets by introducing a block-based reconstruction approach. This makes the method practical for large datasets. Our reconstruction will be smooth across blocks. We give reconstruction measurements as error estimations based on different parameter settings and also an insight on the computational effort. We show that the block size used in reconstruction has a negligible effect on the reconstruction error. Finally we show rendering results to emphasize the quality of this 3D reconstruction technique. 相似文献
25.
Organo-functional silanes which were able to form chemical bonds with kaolinite and could also have an affinity to the materials of concern here, were studied by the sol-gel process. Polymethacrylate with trialkoxy silyl functional groups were prepared, hydrolysed and co-condensed with kaolinite. The progress of the hydrolysis, which proceeded very slowly, was followed by Karl-Fischer titration. Thermal behavior was investigated by differential thermal analysis. The extent of the reaction leading to network formation was qualitatively followed by Fourier transform-infrared spectroscopy and X-ray diffraction. Free-radical polymerization was carried out ultrasonically in the presence of a catalyst. Trimethoxy silane end-capped silane was found to be covalently bonded to kaolinite. The copolymers, with various amounts of kaolinite, were then hydrolysed and co-condensed in the presence of a catalyst to yield sol-gel materials which have a controllable combination of properties of both the polymer and kaolinite. 相似文献
26.
Messing Karen Lefrançois Mélanie Saint-Charles Johanne 《Computer Supported Cooperative Work (CSCW)》2021,30(2):215-249
Computer Supported Cooperative Work (CSCW) - Work activity ergonomics (sometimes called francophone ergonomics) draws heavily on observation in order to support transformation of work to arrive at... 相似文献
27.
Prof. Alessia Carocci Dr. Mariagrazia Roselli Prof. Roberta Budriesi Dr. Matteo Micucci Prof. Jean-François Desaphy Dr. Concetta Altamura Dr. Maria Maddalena Cavalluzzi Dr. Maddalena Toma Dr. Giovanna Ilaria Passeri Dr. Gualtiero Milani Dr. Angelo Lovece Prof. Alessia Catalano Dr. Claudio Bruno Dr. Annalisa De Palma Prof. Filomena Corbo Prof. Carlo Franchini Prof. Solomon Habtemariam Prof. Giovanni Lentini 《ChemMedChem》2021,16(3):578-588
Under the hypothesis that cardioprotective agents might benefit from synergism between antiarrhythmic activity and antioxidant properties, a small series of mexiletine analogues were coupled with the 2,2,5,5-tetramethylpyrroline moiety, known for its antioxidant effect, in order to obtain dual-acting drugs potentially useful in the protection of the heart against post-ischemic reperfusion injury. The pyrroline derivatives reported herein were found to be more potent as antiarrhythmic agents than mexiletine and displayed antioxidant activity. The most interesting tetramethylpyrroline congener, a tert-butyl-substituted analogue, was at least 100 times more active as an antiarrhythmic than mexiletine. 相似文献
28.
The γ-aminobutyric acid type A receptor (GABAAR) plays a major role in fast inhibitory synaptic transmission and is highly regulated by the neuromodulator dopamine. In this aspect, most of the attention has been focused on the classical intracellular signaling cascades following dopamine G-protein-coupled receptor activation. Interestingly, the GABAAR and dopamine D5 receptor (D5R) have been shown to physically interact in the hippocampus, but whether a functional cross-talk occurs is still debated. In the present study, we use a combination of imaging and single nanoparticle tracking in live hippocampal neurons to provide evidence that GABAARs and D5Rs form dynamic surface clusters. Disrupting the GABAAR–D5R interaction with a competing peptide leads to an increase in the diffusion coefficient and the explored area of both receptors, and a drop in immobile synaptic GABAARs. By means of patch-clamp recordings, we show that this fast lateral redistribution of surface GABAARs correlates with a robust depression in the evoked GABAergic currents. Strikingly, it also shifts in time the expression of long-term potentiation at glutamatergic synapses. Together, our data both set the plasma membrane as the primary stage of a functional interplay between GABAAR and D5R, and uncover a non-canonical role in regulating synaptic transmission. 相似文献
29.
Rafael S. Pinto João P. Serra João C. Barbosa Renato Gonçalves Maria M. Silva Senentxu Lanceros-Méndez Carlos M. Costa 《大分子材料与工程》2021,306(11):2100372
Considering the high levels of materials used in the fields of electronics and energy storage systems, it is increasingly necessary to take into consideration environmental impact. Thus, it is important to develop devices based on environmentally friendlier materials and/or processes, such as additive manufacturing techniques. In this work, poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) are prepared by direct-ink-writing (DIW) by varying solvent evaporation temperature and fill density percentage. Different morphologies for both polymers are obtained, including dense films and porous membranes, as well as different electroactive β-phase content, thermal and mechanical properties. The dielectric constant and piezoelectric d33 coefficient for dense films reaches up to 16 at 1 kHz and 4 pC N−1, respectively for PVDF-HFP with a fill density of 80 and a solvent evaporation temperature of 50 °C. Porous structures are developed for battery separator membranes in lithium-ion batteries, with a highest ionic conductivity value of 3.8 mS cm−1 for the PVDF-HFP sample prepared with a fill density of 100 and a solvent evaporation temperature of 25 °C, the sample showing an excellent cycling performance. It is demonstrated that electroactive films and membranes can be prepared by direct-ink writing suitable for sensors/actuators and energy storage systems. 相似文献
30.
Energy minimization studies were carried out for a number of Cu clusters using binary and Gray-coded genetic algorithms along
with real coded differential evolution, and their optimized ground state geometries are presented. The potential energy function
is constructed using a two-body interaction methodology, involving both attractive and repulsive pair-potential terms. The
results obtained through the evolutionary algorithms are compared against those obtained earlier using a Monte Carlo technique. 相似文献