全文获取类型
收费全文 | 5224篇 |
免费 | 58篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 59篇 |
综合类 | 1篇 |
化学工业 | 401篇 |
金属工艺 | 70篇 |
机械仪表 | 57篇 |
建筑科学 | 124篇 |
矿业工程 | 15篇 |
能源动力 | 42篇 |
轻工业 | 295篇 |
水利工程 | 31篇 |
石油天然气 | 7篇 |
无线电 | 294篇 |
一般工业技术 | 458篇 |
冶金工业 | 3015篇 |
原子能技术 | 19篇 |
自动化技术 | 398篇 |
出版年
2021年 | 31篇 |
2019年 | 21篇 |
2018年 | 25篇 |
2017年 | 34篇 |
2016年 | 17篇 |
2015年 | 34篇 |
2014年 | 59篇 |
2013年 | 151篇 |
2012年 | 103篇 |
2011年 | 104篇 |
2010年 | 60篇 |
2009年 | 62篇 |
2008年 | 89篇 |
2007年 | 106篇 |
2006年 | 103篇 |
2005年 | 74篇 |
2004年 | 80篇 |
2003年 | 91篇 |
2002年 | 82篇 |
2001年 | 61篇 |
2000年 | 54篇 |
1999年 | 136篇 |
1998年 | 958篇 |
1997年 | 537篇 |
1996年 | 348篇 |
1995年 | 229篇 |
1994年 | 149篇 |
1993年 | 197篇 |
1992年 | 66篇 |
1991年 | 65篇 |
1990年 | 73篇 |
1989年 | 68篇 |
1988年 | 62篇 |
1987年 | 54篇 |
1986年 | 46篇 |
1985年 | 72篇 |
1984年 | 28篇 |
1983年 | 23篇 |
1982年 | 36篇 |
1981年 | 50篇 |
1980年 | 46篇 |
1979年 | 27篇 |
1978年 | 32篇 |
1977年 | 104篇 |
1976年 | 156篇 |
1975年 | 28篇 |
1974年 | 23篇 |
1973年 | 28篇 |
1972年 | 19篇 |
1971年 | 18篇 |
排序方式: 共有5286条查询结果,搜索用时 0 毫秒
101.
This paper presents an industrial application of simulation-based optimization (SBO) in the scheduling and real-time rescheduling of a complex machining line in an automotive manufacturer in Sweden. Apart from generating schedules that are robust and adaptive, the scheduler must be able to carry out rescheduling in real time in order to cope with the system uncertainty effectively. A real-time scheduling system is therefore needed to support not only the work of the production planner but also the operators on the shop floor by re-generating feasible schedules when required. This paper describes such a real-time scheduling system, which is in essence a SBO system integrated with the shop floor database system. The scheduling system, called OPTIMISE scheduling system (OSS), uses real-time data from the production line and sends back expert suggestions directly to the operators through Personal Digital Assistants (PDAs). The user interface helps in generating new schedules and enables the users to easily monitor the production progress through visualization of production status and allows them to forecast and display target performance measures. Initial results from this industrial application have shown that such a novel scheduling system can help both in improving the line throughput efficiently and simultaneously supporting real-time decision making. 相似文献
102.
103.
Studied 180 reviews of books written by male, female, or male and female authors to investigate sex bias. Half the books had been reviewed by males, half by females. Each review was rated separately for positive and negative elements. For positive elements, there was a significant interaction between author's and reviewer's sex: same-sex books were more favorably evaluated than other-sex books, while books of mixed authorship fell in between. There was no comparable interaction for negative elements. Reviewers of both sexes tended to find more negative elements in books by male than by female authors. It is concluded that unlike in studies employing hypothetical situations, in real-life settings each sex is biased in favor of itself. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
A major goal of robotics research is to develop techniques that allow non-experts to teach robots dexterous skills. In this paper, we report our progress on the development of a framework which exploits human sensorimotor learning capability to address this aim. The idea is to place the human operator in the robot control loop where he/she can intuitively control the robot, and by practice, learn to perform the target task with the robot. Subsequently, by analyzing the robot control obtained by the human, it is possible to design a controller that allows the robot to autonomously perform the task. First, we introduce this framework with the ball-swapping task where a robot hand has to swap the position of the balls without dropping them, and present new analyses investigating the intrinsic dimension of the ball-swapping skill obtained through this framework. Then, we present new experiments toward obtaining an autonomous grasp controller on an anthropomorphic robot. In the experiments, the operator directly controls the (simulated) robot using visual feedback to achieve robust grasping with the robot. The data collected is then analyzed for inferring the grasping strategy discovered by the human operator. Finally, a method to generalize grasping actions using the collected data is presented, which allows the robot to autonomously generate grasping actions for different orientations of the target object. 相似文献
105.
An interative method to fit the function \documentclass{article}\pagestyle{empty}\begin{document}$\mathop \[y = \sum\nolimits_i^n { = 1} a_i e^{lix}\] $\end{document} to data is considered. The technique used is that of inversion of a linear differential operator with constant coefficients. This method reproduces the parameters for mathematically precise data and gives satisfactory results when the data are affected by random errors. 相似文献
106.
The adhesive fracture energy, Gc, is determined from two types of elastic-plastic peel tests (i.e. the single-arm 90° and T-peel methods) and a linear-elastic fracture-mechanics (LEFM) test method (i.e. the tapered double-cantilever beam, TDCB method). A rubber-toughened epoxy adhesive, with both aluminium-alloy and steel substrates, has been used in the present work to manufacture the bonded joints. The peel tests are then modelled using numerical methods. The overall approach to modelling the elastic-plastic peel tests is to employ a finite-element analysis (FEA) approach and to model the crack advance through the adhesive layer via a node-release technique, based upon attaining a critical plastic strain in the element immediately ahead of the crack tip. It is shown that this ‘critical plastic strain fracture model (CPSFM)’ results in predicted values of the steady-state peel loads which are in excellent agreement with the experimentally-measured values. Also, the resulting values of Gc, as determined using the FEA CPSFM approach, have been found to be in excellent agreement with values from previously-reported analytical and direct-measurement methods. Further, it has been found that the calculated values of Gc are independent of whether a standard LEFM test or an elastic-plastic peel test method is employed. Therefore, it has been demonstrated that the value of the adhesive fracture energy, Gc, is independent of the geometric parameters studied and the value of Gc is indeed a characteristic of the joint, in this case for cohesive fracture through the adhesive layer. Finally, it is noted that the FEA CPSFM approach promises considerable potential for the analysis of peel tests which involve very extensive plastic deformation of the peeling arm and for analysing, and predicting, the performance of more complex adhesively-bonded geometries which involve extensive plastic deformation of the substrates. 相似文献
107.
Muller Jeff M.; Brunelli Susan A; Moore Holly; Myers Michael M.; Shair Harry N. 《Canadian Metallurgical Quarterly》2005,119(5):1384
Although dopamine is necessary for mammalian adult pair-bond formation and maternal behavior, its function in infant social behavior and attachment has been less thoroughly explored. The vocalization rate of an isolated rat pup is influenced by recent social contact. Interactions with the dam potentiate vocalization rate. Interactions with littermates or adult males do not. Systemic administration of the D2-family agonist quinpirole specifically blocked maternal potentiation at doses that did not alter vocalization rate in an isolation prior to dam contact. This result was not explained by quinpirole's effects on body temperature or locomotion. The results are consistent with a role for dopamine in infant social behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
Lacreuse Agnès; Kim Charles B.; Rosene Douglas L.; Killiany Ronald J.; Moss Mark B.; Moore Tara L.; Chennareddi Lakshmi; Herndon James G. 《Canadian Metallurgical Quarterly》2005,119(1):118
The authors tested 90 rhesus monkeys (Macaca mulatta) on a task of spatial memory, the spatial Delayed Recognition Span Test. The results showed that performance declined significantly with age, males had greater scores than females, and the rate of apparent decline with age was greater in males than in females. Both working and reference memory declined with age, but only working memory showed sex differences. The authors compared these data with that of 22 monkeys who were trained on a simpler version of the task before formal testing. Training had no effect on males but dramatically improved working memory in young females. The results confirm a male advantage in spatial working memory at a young age and confirm a greater decline with age in males than in females. It is important to note that prior training completely reverses the deficits of young females. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
109.
Olson Ingrid R.; Jiang Yuhong; Moore Katherine Sledge 《Canadian Metallurgical Quarterly》2005,31(5):889
The ability to remember visual stimuli over a short delay period is limited by the small capacity of visual working memory (VWM). Here the authors investigate the role of learning in enhancing VWM. Participants saw 2 spatial arrays separated by a 1-s interval. The 2 arrays were identical except for 1 location. Participants had to detect the difference. Unknown to the participants, some spatial arrays would repeat once every dozen trials or so for up to 32 repetitions. Spatial VWM performance increased significantly when the same location changed across display repetitions, but not at all when different locations changed from one display repetition to another. The authors suggest that a major role of learning in VWM is to mediate which information gets retained, rather than to directly increase VWM capacity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
110.