全文获取类型
收费全文 | 3513篇 |
免费 | 201篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 52篇 |
综合类 | 3篇 |
化学工业 | 991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 | 154篇 |
轻工业 | 267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 | 35篇 |
自动化技术 | 654篇 |
出版年
2023年 | 28篇 |
2022年 | 80篇 |
2021年 | 105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 | 282篇 |
2010年 | 182篇 |
2009年 | 217篇 |
2008年 | 228篇 |
2007年 | 169篇 |
2006年 | 181篇 |
2005年 | 126篇 |
2004年 | 110篇 |
2003年 | 103篇 |
2002年 | 122篇 |
2001年 | 55篇 |
2000年 | 51篇 |
1999年 | 49篇 |
1998年 | 67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 | 9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3720条查询结果,搜索用时 15 毫秒
131.
Hossein Azadi Sanne de Jong Ben Derudder Philippe De Maeyer Frank Witlox 《Renewable & Sustainable Energy Reviews》2012,16(6):3599-3603
While biofuels have currently been regarded as a good alternative for fossil fuels, there remain many debates on their impacts on human and environment. This paper tried to shed light on bio-ethanol in Brazil as one of the main producers and exporters in the world. The main question was to understand “how sustainable is bio-ethanol production in Brazil?” To answer, the political motives of producing bio-ethanol followed by its ecological and socio-economic impacts were discussed. The paper concluded that although bio-ethanol production in Brazil seems environmentally friendly, it might socio-economically be hazardous. 相似文献
132.
The aim of this paper is the predictive control of Timed Event Graphs with specifications defined by P-time Event Graphs. We propose a fixed-point approach which leads to a pseudo-polynomial algorithm. As the performance of the algorithm is crucial in on-line control, we highlight an important case where the resolution of this first algorithm is efficient. The second technique is a space controller on a horizon leading to a strongly polynomial algorithm. 相似文献
133.
Jnyana Ranjan Pati Subhajit Dutta Philippe Eliaers Pinakeswar Mahanta Pradip Kumar Chatterjee 《Drying Technology》2016,34(9):1073-1084
The intensification of interfacial mass, heat, and momentum transfer makes vortex chambers potentially interesting for the efficient drying of paddy, allowing shorter drying times and/or more compact equipment. The presence of a shell introduces particular challenges. Intraparticle diffusion limitations are strong and may reduce the advantage from intensified interfacial mass and heat transfer and the efficiency of air usage. Furthermore, high shear and normal stresses in the fast rotating particle bed may cause damage to the paddy shell, posing problems for transport and storage. With these specific aspects in mind, the use of vortex chambers for paddy drying is experimentally evaluated. 相似文献
134.
135.
136.
137.
We solve the problem of finding the lowest stable-equilibrium pose of a rigid body subjected to gravity and suspended in space by an arbitrary number of cables. Besides representing a contribution to fundamental rigid-body mechanics, this solution finds application in two areas of robotics research: underconstrained cable-driven parallel robots and cooperative towing. The proposed approach consists in globally minimizing the rigid-body potential energy. This is done by applying a branch-and-bound algorithm over the group of rotations, which is partitioned into boxes in the space of Euler-Rodrigues parameters. The lower bound on the objective is obtained through a semidefinite relaxation of the optimization problem, whereas the upper bound is obtained by solving the same problem for a fixed orientation. The resulting algorithm is applied to several examples drawn from the literature. The reported Matlab implementation converges to the lowest stable equilibrium pose generally in a few seconds for cable-robot applications. Interestingly, the proposed method is only mildly sensitive to the number of suspending cables, which is shown by solving an example with 1000 cables in two hours. 相似文献
138.
Discovery of Heterocyclic Nonacetamide Synaptic Vesicle Protein 2A (SV2A) Ligands with Single‐Digit Nanomolar Potency: Opening Avenues towards the First SV2A Positron Emission Tomography (PET) Ligands
下载免费PDF全文
![点击此处可从《ChemMedChem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Joël Mercier Laurence Archen Véronique Bollu Stéphane Carré Yves Evrard Dr. Eric Jnoff Dr. Benoît Kenda Bénédicte Lallemand Dr. Philippe Michel Dr. Florian Montel Dr. Florence Moureau Nathalie Price Dr. Yannick Quesnel Dr. Xavier Sauvage Dr. Anne Valade Dr. Laurent Provins 《ChemMedChem》2014,9(4):693-698
The role of the synaptic vesicle protein 2A (SV2A) protein, target of the antiepileptic drug levetiracetam, is still mostly unknown. Considering its potential to provide in vivo functional insights into the role of SV2A in epileptic patients, the development of an SV2A positron emission tomography (PET) tracer has been undertaken. Using a 3D pharmacophore model based on close analogues of levetiracetam, we report the rationale design of three heterocyclic non‐acetamide lead compounds, UCB‐A, UCB‐H and UCB‐J, the first single‐digit nanomolar SV2A ligands with suitable properties for development as PET tracers. 相似文献
139.
140.