全文获取类型
收费全文 | 7473篇 |
免费 | 336篇 |
国内免费 | 16篇 |
专业分类
电工技术 | 85篇 |
综合类 | 3篇 |
化学工业 | 1463篇 |
金属工艺 | 142篇 |
机械仪表 | 99篇 |
建筑科学 | 351篇 |
矿业工程 | 17篇 |
能源动力 | 238篇 |
轻工业 | 1255篇 |
水利工程 | 50篇 |
石油天然气 | 11篇 |
无线电 | 615篇 |
一般工业技术 | 1391篇 |
冶金工业 | 710篇 |
原子能技术 | 41篇 |
自动化技术 | 1354篇 |
出版年
2023年 | 70篇 |
2022年 | 85篇 |
2021年 | 175篇 |
2020年 | 123篇 |
2019年 | 140篇 |
2018年 | 185篇 |
2017年 | 177篇 |
2016年 | 264篇 |
2015年 | 202篇 |
2014年 | 269篇 |
2013年 | 481篇 |
2012年 | 443篇 |
2011年 | 495篇 |
2010年 | 436篇 |
2009年 | 400篇 |
2008年 | 428篇 |
2007年 | 361篇 |
2006年 | 309篇 |
2005年 | 253篇 |
2004年 | 222篇 |
2003年 | 194篇 |
2002年 | 189篇 |
2001年 | 94篇 |
2000年 | 107篇 |
1999年 | 87篇 |
1998年 | 160篇 |
1997年 | 109篇 |
1996年 | 114篇 |
1995年 | 62篇 |
1994年 | 69篇 |
1993年 | 58篇 |
1992年 | 40篇 |
1991年 | 39篇 |
1990年 | 26篇 |
1989年 | 33篇 |
1987年 | 34篇 |
1986年 | 28篇 |
1985年 | 30篇 |
1984年 | 31篇 |
1982年 | 31篇 |
1979年 | 24篇 |
1976年 | 33篇 |
1936年 | 29篇 |
1935年 | 32篇 |
1931年 | 25篇 |
1930年 | 24篇 |
1928年 | 46篇 |
1927年 | 36篇 |
1913年 | 49篇 |
1912年 | 28篇 |
排序方式: 共有7825条查询结果,搜索用时 15 毫秒
31.
A discrete Laplace‐Beltrami operator is called perfect if it possesses all the important properties of its smooth counterpart. It is known which triangle meshes admit perfect Laplace operators and how to fix any other mesh by changing the combinatorics. We extend the characterization of meshes that admit perfect Laplacians to general polygon meshes. More importantly, we provide an algorithm that computes a perfect Laplace operator for any polygon mesh without changing the combinatorics, although, possibly changing the embedding. We evaluate this algorithm and demonstrate it at applications. 相似文献
32.
33.
Anuja Hariharan Marc Thomas Philipp Adam Timm Teubner Christof Weinhardt 《Electronic Markets》2016,26(4):339-355
Environmental conditions and the interplay of cognitive and affective processes both exert influences on bidding behavior. This paper brings the above together, considering how the (external) auction environment determines the impact of (internal) cognitive and affective processes on bidding behavior, assessed in comparison to the optimal bid. Two aspects of the auction environment were considered, namely auction dynamics (low: first-price sealed-bid auction, high: Dutch auction) and value uncertainty (low, high). In a laboratory experiment, we assess bidders’ cognitive workload and emotional arousal through physiological measurements. We find that higher auction dynamics increase the impact of emotional arousal on bid deviations, but not that of cognitive workload. Higher value uncertainty, conversely, increases the impact of cognitive workload on bid deviations, but not that of emotional arousal. Taken together, the auction environment is a critical factor in understanding the nature of the underlying decision process and its impact on bids. 相似文献
34.
Rachel?BawdenEmail authorView authors OrcID profile Chloé?Clavel Frédéric?Landragin 《Language Resources and Evaluation》2016,50(4):821-838
We present a corpus-based prosodic analysis with the aim of uncovering the relationship between dialogue acts, personality and prosody in view to providing guidelines for the ECA Greta’s text-to-speech system. The corpus used is the SEMAINE corpus, featuring four different personalities, further annotated for dialogue acts and prosodic features. In order to show the importance of the choice of dialogue act taxonomy, two different taxonomies were used, the first corresponding to Searle’s taxonomy of speech acts and the second, inspired by Bunt’s DIT++, including a division of directive acts into finer categories. Our results show that finer-grained distinctions are important when choosing a taxonomy. We also show with some preliminary results that the prosodic correlates of dialogue acts are not always as cited in the literature and prove more complex and variable. By studying the realisation of different directive acts, we also observe differences in the communicative strategies of the ECA depending on personality, in view to providing input to a speech system. 相似文献
35.
Boris Hudec Chung-Wei Hsu I-Ting Wang Wei-Li Lai Che-Chia Chang Taifang Wang Karol Fröhlich Chia-Hua Ho Chen-Hsi Lin Tuo-Hung Hou 《中国科学:信息科学(英文版)》2016,59(6):061403
In this article, we comprehensively review recent progress in the ReRAM cell technology for 3D integration focusing on a material/device level. First we briefly mention pioneering work on high-density crossbar ReRAM arrays which paved the way to 3D integration. We discuss the two main proposed 3D integration schemes—3D horizontally stacked ReRAM vs 3D Vertical ReRAM and their respective advantages and disadvantages. We follow with the detailed memory cell design on important work in both areas, utilizing either filamentary or interface-limited switching mechanisms. We also discuss our own contributions on HfO2-based filamentary 3D Vertical ReRAM as well as TaOx/TiO2 bilayer-based self-rectifying 3D Vertical ReRAM. Finally, we summarize the present status and provide an outlook for the nearterm future. 相似文献
36.
Aurélien Plyer Guy Le Besnerais Frédéric Champagnat 《Journal of Real-Time Image Processing》2016,11(4):713-730
This paper deals with dense optical flow estimation from the perspective of the trade-off between quality of the estimated flow and computational cost which is required by real-world applications. We propose a fast and robust local method, denoted by eFOLKI, and describe its implementation on GPU. It leads to very high performance even on large image formats such as 4 K (3,840 × 2,160) resolution. In order to assess the interest of eFOLKI, we first present a comparative study with currently available GPU codes, including local and global methods, on a large set of data with ground truth. eFOLKI appears significantly faster while providing quite accurate and highly robust estimated flows. We then show, on four real-time video processing applications based on optical flow, that eFOLKI reaches the requirements both in terms of estimated flows quality and of processing rate. 相似文献
37.
Frederik Verbist Nikos Deligiannis Marc Jacobs Joeri Barbarien Peter Schelkens Adrian Munteanu Jan Cornelis 《Multimedia Tools and Applications》2013,66(3):405-430
Distributed video coding (DVC) constitutes an original coding framework to meet the stringent requirements imposed by uplink-oriented and low-power mobile video applications. The quality of the side information available to the decoder and the efficiency of the employed channel codes are primary factors determining the success of a DVC system. This contribution introduces two novel techniques for probabilistic motion compensation in order to generate side information at the Wyner-Ziv decoder. The employed DVC scheme uses a base layer, serving as a hash to facilitate overlapped block motion estimation at the decoder side. On top of the base layer, a supplementary Wyner-Ziv layer is coded in the DCT domain. Both proposed probabilistic motion compensation techniques are driven by the actual correlation channel statistics and reuse information contained in the hash. Experimental results report significant rate savings caused by the novel side information generation methods compared to previous techniques. Moreover, the compression performance of the presented DVC architecture, featuring the proposed side-information generation techniques, delivers state-of-the-art compression performance. 相似文献
38.
Françoise Détienne Béatrice Cahour Marie-Christine Legout Bernard Gourvennec Marc Relieu Gilles Coppin 《Cognition, Technology & Work》2013,15(4):445-455
Based on the analysis of “real” Second Life meetings data, in educational and professional settings, our objective is to understand the actual uses of this kind of Virtual World and more particularly, the interactive frames constructed in SL meetings and their interrelation with uses of communication media. The originality of our analytical framework stems from the combination of two perspectives: a third view perspective based on analyses of observational data and a first view perspective based on users’ reports on their experience in SL. Our results highlight: boundaries between serious and recreational registers; avatar’s expression and attribution of feelings to the person “behind”; spatial positioning as indicators and constructors of roles and engagement; management of communication fluidity and joint focus; narrowing of communication media used for task focus content; emerging mediation role for management of fractured exchanges. 相似文献
39.
Aerial photographs and images are used by a variety of industries, including farming, landscaping, surveying, and agriculture, as well as academic researchers including archaeologists and geologists. Aerial imagery can provide a valuable resource for analyzing sites of interest and gaining information about the structure, layout, and composition of large areas of land that would be unavailable otherwise. Current methods of acquiring aerial images rely on techniques such as satellite imagery, manned aircraft, or more recently unmanned aerial vehicles (UAVs) and micro‐UAV technologies. These solutions, while accurate and reliable, have several drawbacks. Using satellite imagery or UAVs can prove to be very expensive, costing tens of thousands for images. They can also prove to be time‐consuming and in some cases have constraints on use, such as no‐fly zones. In this paper, we present an alternative low‐cost, versatile solution to these methods, an intelligent kite aerial photography platform (iKAPP), for the purpose of acquiring aerial images and monitoring sites of interest. We show how this system provides flexibility in application, and we detail the system's design, mechanical operation, and initial flight experiments for a low‐cost, lightweight, intelligent platform capable of acquiring high‐resolution images. Finally, we demonstrate the system by acquiring images of a local site, showing how the system functions and the quality of images it can capture. The application of the system and its capabilities in terms of capture rates, image quality, and limitations are also presented. The system offers several improvements over traditional KAP systems, including onboard “intelligent” processing and communications. The intelligent aspect of this system stems from the use of self‐image stabilization of the camera, the advantage being that one is able to configure the system to capture large areas of a site automatically, and one can see the site acquisition in real time, all of which are not possible with previous methods of AP. © 2013 Wiley Periodicals, Inc. 相似文献
40.
A comparison of broad versus deep auditory menu structures 总被引:1,自引:0,他引:1
OBJECTIVE: The primary purpose of this experiment was to gain a greater understanding of the utilization of working memory when interacting with a speech-enabled interactive voice response (IVR) system. BACKGROUND: A widely promoted guideline advises limiting IVR menus to five or fewer items because of constraints of the human memory system, commonly citing Miller's (1956) paper. The authors argue that Miller's paper does not, in fact, support this guideline. Furthermore, applying modern theories of working memory leads to the opposite conclusion--that reducing menu length by creating a deeper structure is actually more demanding of users' working memories and leads to poorer performance and satisfaction. METHOD: Participants took a working memory capacity test and then attempted to complete a series of e-mail tasks using one of two IVR designs (functionally equivalent, but one with a broad menu structure and the other with a deep structure). RESULTS: Users of the broad-structure IVR performed better and were more satisfied than users of the deep-structure IVR. Furthermore, this effect was more pronounced for those with low working memory capacity. CONCLUSION: Results indicate that creating a deeper structure is more demanding of working memory resource than the alternative of longer, shallower menus. APPLICATION: This experiment has important practical implications for all systems with auditory menus (particularly IVRs) because it provides empirical evidence refuting a widely promoted design practice. 相似文献