全文获取类型
收费全文 | 2617篇 |
免费 | 214篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 22篇 |
综合类 | 1篇 |
化学工业 | 585篇 |
金属工艺 | 70篇 |
机械仪表 | 101篇 |
建筑科学 | 92篇 |
矿业工程 | 10篇 |
能源动力 | 147篇 |
轻工业 | 415篇 |
水利工程 | 10篇 |
石油天然气 | 19篇 |
无线电 | 424篇 |
一般工业技术 | 463篇 |
冶金工业 | 45篇 |
原子能技术 | 20篇 |
自动化技术 | 410篇 |
出版年
2024年 | 14篇 |
2023年 | 47篇 |
2022年 | 47篇 |
2021年 | 125篇 |
2020年 | 91篇 |
2019年 | 93篇 |
2018年 | 151篇 |
2017年 | 116篇 |
2016年 | 139篇 |
2015年 | 112篇 |
2014年 | 126篇 |
2013年 | 477篇 |
2012年 | 110篇 |
2011年 | 105篇 |
2010年 | 136篇 |
2009年 | 145篇 |
2008年 | 67篇 |
2007年 | 55篇 |
2006年 | 43篇 |
2005年 | 27篇 |
2004年 | 22篇 |
2003年 | 14篇 |
2002年 | 19篇 |
2001年 | 77篇 |
2000年 | 74篇 |
1999年 | 74篇 |
1998年 | 80篇 |
1997年 | 78篇 |
1996年 | 21篇 |
1995年 | 7篇 |
1994年 | 12篇 |
1993年 | 11篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1973年 | 4篇 |
1968年 | 4篇 |
排序方式: 共有2834条查询结果,搜索用时 15 毫秒
51.
Murat Kalender Ahmed Kheiri Ender Özcan Edmund K. Burke 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2013,17(12):2279-2292
Educational timetabling problem is a challenging real world problem which has been of interest to many researchers and practitioners. There are many variants of this problem which mainly require scheduling of events and resources under various constraints. In this study, a curriculum based course timetabling problem at Yeditepe University is described and an iterative selection hyper-heuristic is presented as a solution method. A selection hyper-heuristic as a high level methodology operates on the space formed by a fixed set of low level heuristics which operate directly on the space of solutions. The move acceptance and heuristic selection methods are the main components of a selection hyper-heuristic. The proposed hyper-heuristic in this study combines a simulated annealing move acceptance method with a learning heuristic selection method and manages a set of low level constraint oriented heuristics. A key goal in hyper-heuristic research is to build low cost methods which are general and can be reused on unseen problem instances as well as other problem domains desirably with no additional human expert intervention. Hence, the proposed method is additionally applied to a high school timetabling problem, as well as six other problem domains from a hyper-heuristic benchmark to test its level of generality. The empirical results show that our easy-to-implement hyper-heuristic is effective in solving the Yeditepe course timetabling problem. Moreover, being sufficiently general, it delivers a reasonable performance across different problem domains. 相似文献
52.
With the emergence of new media, interactive film projects have mainly struggled to resolve the contradiction between dramatic structures and interaction. Dramatic film presents identification with the main character, where the viewer is constantly oppressed by the narrative, and therefore lost in illusion. In this context, when we bring on the scene interaction, the drama apparently starts to lose its power. In this article, a new interactive film model based on Brechtian film theory is proposed. This model presents a new way of spatiotemporal construction where different audiovisual combinations can be viewed successively, and this way the viewer can actively construct his/her own story. Theoretical framework of the Brechtian interactive film model is supported by an interactive film application, named Academia. The main feature of the model is that, while interaction is very simple, the continuity of the narrative is preserved and the film requiring an intellectual level of interpretation. 相似文献
53.
Esen Gökçe Özdamar 《Digital Creativity》2013,24(3):206-212
ABSTRACTThis exhibition review focuses on the quest for weaving boundaries between body-form-space-and material relationship using immersive technologies. Emerging as an architectural counterpoint, Universal Everything: Fluid Bodies exhibition held in Borusan Contemporary focuses on how we perceive the motion and form in relation to it, as well as fusing senses of kinaesthetic and synaesthetic through a data driven and motion-based visual representation. Through these algorithms, the exhibition displays how neuroarchitecture reminds us of the senses of perception. The architectural counterpoint, intention as an interaction and encounter of the body with ‘the machine’ as the ‘voyeur body’ and how this observational dialogue becomes a research methodology in understanding the nature of movement in space through digital tools. 相似文献
54.
55.
Zafer Iscan Ayhan Yüksel Zümray Dokur Mehmet Korürek Tamer Ölmez 《Digital Signal Processing》2009,19(5):890-901
In this study, a novel incremental supervised neural network (ISNN) is proposed for the segmentation of medical images. Performance of the ISNN is investigated for tissue segmentation in medical images obtained from various imaging modalities. Two feature extraction methods based on transform and moments are comparatively investigated to segment the tissues in medical images. Two-dimensional (2D) continuous wavelet transform (CWT) and the moments of the gray-level histogram (MGH) are computed in order to form the feature vectors of ultrasound (US) bladder and phantom images, X-ray computerized tomography (CT) and magnetic resonance (MR) head images. In the 2D-CWT method, feature vectors are formed by the intensity of one pixel of each wavelet-plane of different energy bands. The MGH represents the tissues within the sub-windows by using the spatial variation of image intensities. In this study, the ISNN and Grow and Learn (GAL) network are employed for the segmentation task. It is observed that the ISNN has significantly eliminated the disadvantages of the GAL network in the segmentation of the medical images. 相似文献
56.
Mehmet Önder Efe 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2009,13(1):23-29
This paper presents an approach to improve the performance of intelligent sliding model control achieved by the use of a fundamental
constituent of soft computing, named Adaptive Linear Element (ADALINE). The proposed scheme is based on the fractional calculus.
A previously considered tuning scheme is revised according to the rules of fractional order differintegration. After a comparison
with the integer order counterpart, it is seen that the control system with the proposed adaptation scheme provides (1) better
tracking performance, (2) suppression of undesired drifts in parameter evolution and (3) a very high degree of robustness
and insensitivity to disturbances. The claims are justified through some simulations utilizing the dynamic model of a two
degrees of freedom (DOF) direct drive robot arm and overall, the contribution of the paper is to introduce the fractional
order calculus into a robust and nonlinear control problem with some outperforming features that are absent when the integer
order differintegration operators are adopted. 相似文献
57.
Summary The polymerization of methyl methacrylate (MMA), ethyl acrylate (EA), styrene (St) and 2-vinyl pyridine (VP) is initiated upon irradiation at >350 nm of dichloromethane solutions containing N-ethoxy-2-methylpyridinium hexafluorophosphate (EMP+PF6
-) and anthracene or thioxanthone. Initiation mechanisms involving the formation of ethoxyl radicals during the decomposition of EMP+ ions via electron transfer are proposed. 相似文献
58.
Emrah Öncü Rasit Tutgun Emre Aktas 《International Journal of Satellite Communications and Networking》2023,41(6):589-598
Conventional solid-state power amplifier (SSPA) design approach isolates radio frequency (RF) design from communication theory. In this paper, a unified SSPA design approach is proposed, which optimizes SSPA parameters (bias voltage and input RF signal power) to minimize total DC power consumption while satisfying received SNR constraint specified by the link budget. The effect of SSPA nonlinearity is quantified by the error vector magnitude measured at its output and the corresponding received SNR degradation is analyzed. Using the quantitative metrics for received SNR, it is possible to evaluate highly nonlinear SSPA classes such as Class-B or deep-Class AB, which are normally not considered in conventional SSPA design approach to be used in satellite communication applications. 相似文献
59.
This article aims to explore the impact of the integration of risk factors into delayed milestones for construction projects. A simulation model was developed to determine the impact of schedule variability on cost estimation. To generate random scenarios a Monte Carlo Simulation (MCS) technique was applied. The developed model computes the cost impact of delayed milestone in the expected budget. Using a risk integration approach revealed the critical time frame that may lead to a budget deficit for a project. As a result, a number of cost-sensitive risk factors and schedule delays were identified for the critical time period where the risk of budget deficit increases. The method of integration proposed in this article highlights the priority of risk factors and schedule delays for construction contracts involving Payments at Event Occurrences (PEO). Consequently, the developed method can be useful for practitioners in anticipation of potential increase of costs, hence, prevention of failure due to budget deficit. 相似文献
60.
A Review of Metal Fabricated with Laser‐ and Powder‐Bed Based Additive Manufacturing Techniques: Process,Nomenclature, Materials,Achievable Properties,and its Utilization in the Medical Sector
下载免费PDF全文
![点击此处可从《Advanced Engineering Materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)