全文获取类型
收费全文 | 264篇 |
免费 | 12篇 |
专业分类
电工技术 | 8篇 |
综合类 | 1篇 |
化学工业 | 80篇 |
机械仪表 | 5篇 |
建筑科学 | 11篇 |
能源动力 | 21篇 |
轻工业 | 26篇 |
水利工程 | 4篇 |
无线电 | 20篇 |
一般工业技术 | 25篇 |
冶金工业 | 22篇 |
原子能技术 | 6篇 |
自动化技术 | 47篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 12篇 |
2013年 | 24篇 |
2012年 | 18篇 |
2011年 | 22篇 |
2010年 | 9篇 |
2009年 | 23篇 |
2008年 | 13篇 |
2007年 | 11篇 |
2006年 | 15篇 |
2005年 | 7篇 |
2004年 | 4篇 |
2003年 | 9篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 11篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 3篇 |
排序方式: 共有276条查询结果,搜索用时 15 毫秒
1.
2.
Pierluigi Guerrini De LucaClaudio Scali 《Chemical engineering science》2002,57(11):2077-2087
Applicability of different temperature oscillation calorimetry algorithms, previously proposed in the literature, for the evaluation of the heat transfer coefficient during the course of the reaction, is analysed by referring to the experimental data from a methyl methacrylate polymerisation reactor.Results are coincident in the nominal case (no errors on data), while differences appear in the elaboration of real data. The effect of uncertainty in the experimental data has been simulated in terms of error on the amplitude and on the phase of reactor and jacket temperature profiles.This approach allows to indicate algorithms having the best robustness properties and to give an explanation of phase errors in terms of a lumped parameter which accounts for different phenomena, not included in the basic hypotheses of the method. Based on this observation, a procedure to eliminate this source of errors from experimental data is proposed for the more general algorithm presented to handle oscillating temperature profiles generated by different techniques. 相似文献
3.
A Iezzi N Magarelli A Carriero PF Podda C Ciccotosto L Bonomo 《Canadian Metallurgical Quarterly》1994,88(1-2):24-30
In an experiment designed to distinguish between the behavioral consequences of treatment with SCH-23390, a D1 dopamine receptor blocker, and raclopride, a D2 antagonist, rats were trained to perform a water-reinforced forelimb operant response. Response rate and the duration of each forelimb contact with the operandum were recorded. In addition, the durations of the rat's visits to the reward well were detected by a photobeam which was blocked by the rat's muzzle as it remained at the reward well. In a between-groups dosing design, separate groups of rats (11-13 rats/group) received SCH-23390 (0, 0.01, 0.02, 0.04, 0.08, 0.12 mg/kg, IP, 30 min) or raclopride (0. 0.05, 0.1, 0.2, 0.4, 0.8 mg/kg, IP, 30 min) for 21 consecutive days. Quantitative analyses indicated that for comparable amounts of operant rate reduction, raclopride had a significantly greater tendency than SCH-23390 to increase the duration of operant responses and to increase the maximum muzzle entry duration (i.e., to induce microcatalepsy). The results support the idea that at relatively low doses D2 antagonism is more likely than D1 antagonism to produce effects identified preclinically with extrapyramidal side effects. 相似文献
4.
Grasso Susanna Claps Pierluigi Ganora Daniele Libertino Andrea 《Water Resources Management》2021,35(2):675-687
Water Resources Management - To reduce the impact of droughts and increase the resilience of regional water systems, various competing demands, such as hydropower, supply, irrigation and river... 相似文献
5.
In this article, a novel technique for user’s authentication and verification using gait as a biometric unobtrusive pattern is proposed. The method is based on a two stages pipeline. First, a general activity recognition classifier is personalized for an specific user using a small sample of her/his walking pattern. As a result, the system is much more selective with respect to the new walking pattern. A second stage verifies whether the user is an authorized one or not. This stage is defined as a one-class classification problem. In order to solve this problem, a four-layer architecture is built around the geometric concept of convex hull. This architecture allows to improve robustness to outliers, modeling non-convex shapes, and to take into account temporal coherence information. Two different scenarios are proposed as validation with two different wearable systems. First, a custom high-performance wearable system is built and used in a free environment. A second dataset is acquired from an Android-based commercial device in a ‘wild’ scenario with rough terrains, adversarial conditions, crowded places and obstacles. Results on both systems and datasets are very promising, reducing the verification error rates by an order of magnitude with respect to the state-of-the-art technologies. 相似文献
6.
In this paper, the design, simulation and experimental tests are presented for THROO: a Tracked Hybrid Rover, which has been developed to Overpass Obstacles. The proposed mobile robot has 3-DOFs and it is capable of straight motion, turning ability and two operations, namely rover-like motion with tracks on flat terrain and walking-like motion with track and legs to overpass obstacles to move on uneven terrain. The leg mechanism is composed of a four-bar linkage, which has been synthesized according to the desired features. In particular, the Burmester problem, which aims at finding the geometric parameters of a four-bar linkage required for a prescribed set of finitely separated poses are solved for the case understudy. Dynamic simulations have been carried out and a prototype has been built. The proposed results show the hybrid rover ability to overpass obstacles, for which size is comparable or greater than the track high. 相似文献
7.
In studies of feeding by the bark beetle, Ips paraconfusus, two pine stilbenes (pinosylvin and pinosylvin methyl ether), ferulic acid glucoside, and enantiomers of the four most common sugars present in ponderosa pine phloem (sucrose, glucose, fructose, and raffinose) did not stimulate or reduce male feeding when assayed on wet -cellulose with or without stimulatory phloem extractives present. When allowed to feed on wet -cellulose containing sequential extracts (hexane, methanol, and water) of ponderosa pine phloem, methanol and water extractives stimulated feeding, but hexane extractives did not. Males confined in wet -cellulose containing aqueous or organic extracts of culture broths derived from phloem tissue and containing the root pathogen, Heterobasidion annosum, ingested less substrate than beetles confined to control preparations. In an assay using logs from uninoculated ponderosa pines, the mean lengths of phloem in the digestive tracts increased as time spent feeding increased. Males confined to the phloem of basal logs cut from ponderosa pines artificially inoculated with H. annosum ingested significantly less phloem than beetles in logs cut from trees that were (combined) mock-inoculated or uninoculated and did not contain the pathogen. However, individual pathogen-containing treatments were not significantly different from uninoculated controls. It was concluded that altered feeding rates are not a major factor which may explain why diseased ponderosa pines are colonized by I. paraconfusus. 相似文献
8.
Recently, some studies linked the computational power of abstract computing systems based on multiset rewriting to models of Petri nets and the computation power of these nets to their topology. In turn, the computational power of these abstract computing devices can be understood by just looking at their topology, that is, information flow.Here we continue this line of research by introducing J languages and proving that they can be accepted by place/transition systems whose underlying net is composed only by join. Moreover, we study how J languages relate to other families of formal languages. 相似文献
9.
Design and control of an IPMC wormlike robot. 总被引:2,自引:0,他引:2
Paolo Arena Claudia Bonomo Luigi Fortuna Mattia Frasca Salvatore Graziani 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2006,36(5):1044-1052
This paper presents an innovative wormlike robot controlled by cellular neural networks (CNNs) and made of an ionic polymer-metal composite (IPMC) self-actuated skeleton. The IPMC actuators, from which it is made of, are new materials that behave similarly to biological muscles. The idea that inspired the work is the possibility of using IPMCs to design autonomous moving structures. CNNs have already demonstrated their powerfulness as new structures for bio-inspired locomotion generation and control. The control scheme for the proposed IPMC moving structure is based on CNNs. The wormlike robot is totally made of IPMCs, and each actuator has to carry its own weight. All the actuators are connected together without using any other additional part, thereby constituting the robot structure itself. Worm locomotion is performed by bending the actuators sequentially from "tail" to "head," imitating the traveling wave observed in real-world undulatory locomotion. The activation signals are generated by a CNN. In the authors' opinion, the proposed strategy represents a promising solution in the field of autonomous and light structures that are capable of reconfiguring and moving in line with spatial-temporal dynamics generated by CNNs. 相似文献
10.