全文获取类型
收费全文 | 13413篇 |
免费 | 728篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 138篇 |
综合类 | 10篇 |
化学工业 | 3376篇 |
金属工艺 | 254篇 |
机械仪表 | 243篇 |
建筑科学 | 492篇 |
矿业工程 | 18篇 |
能源动力 | 477篇 |
轻工业 | 2223篇 |
水利工程 | 106篇 |
石油天然气 | 41篇 |
无线电 | 649篇 |
一般工业技术 | 2120篇 |
冶金工业 | 1634篇 |
原子能技术 | 81篇 |
自动化技术 | 2297篇 |
出版年
2024年 | 18篇 |
2023年 | 87篇 |
2022年 | 441篇 |
2021年 | 518篇 |
2020年 | 296篇 |
2019年 | 352篇 |
2018年 | 529篇 |
2017年 | 490篇 |
2016年 | 536篇 |
2015年 | 362篇 |
2014年 | 544篇 |
2013年 | 844篇 |
2012年 | 827篇 |
2011年 | 966篇 |
2010年 | 685篇 |
2009年 | 673篇 |
2008年 | 609篇 |
2007年 | 559篇 |
2006年 | 459篇 |
2005年 | 398篇 |
2004年 | 312篇 |
2003年 | 288篇 |
2002年 | 262篇 |
2001年 | 193篇 |
2000年 | 187篇 |
1999年 | 171篇 |
1998年 | 632篇 |
1997年 | 384篇 |
1996年 | 287篇 |
1995年 | 167篇 |
1994年 | 137篇 |
1993年 | 141篇 |
1992年 | 57篇 |
1991年 | 60篇 |
1990年 | 55篇 |
1989年 | 50篇 |
1988年 | 40篇 |
1987年 | 38篇 |
1986年 | 41篇 |
1985年 | 41篇 |
1984年 | 33篇 |
1983年 | 34篇 |
1982年 | 38篇 |
1981年 | 46篇 |
1980年 | 36篇 |
1979年 | 17篇 |
1978年 | 20篇 |
1977年 | 38篇 |
1976年 | 62篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Julian J. McAuley Arnau Ramisa Tibério S. Caetano 《International Journal of Computer Vision》2013,104(3):343-361
The recently proposed ImageNet dataset consists of several million images, each annotated with a single object category. These annotations may be imperfect, in the sense that many images contain multiple objects belonging to the label vocabulary. In other words, we have a multi-label problem but the annotations include only a single label (which is not necessarily the most prominent). Such a setting motivates the use of a robust evaluation measure, which allows for a limited number of labels to be predicted and, so long as one of the predicted labels is correct, the overall prediction should be considered correct. This is indeed the type of evaluation measure used to assess algorithm performance in a recent competition on ImageNet data. Optimizing such types of performance measures presents several hurdles even with existing structured output learning methods. Indeed, many of the current state-of-the-art methods optimize the prediction of only a single output label, ignoring this ‘structure’ altogether. In this paper, we show how to directly optimize continuous surrogates of such performance measures using structured output learning techniques with latent variables. We use the output of existing binary classifiers as input features in a new learning stage which optimizes the structured loss corresponding to the robust performance measure. We present empirical evidence that this allows us to ‘boost’ the performance of binary classification on a variety of weakly-supervised labeling problems defined on image taxonomies. 相似文献
992.
993.
Ákos Szőke András Förhécz Gábor Kőrösi György Strausz 《Artificial Intelligence and Law》2013,21(4):485-519
Regulations affect every aspect of our lives. Compliance with the regulations impacts citizens and businesses similarly: they have to find their rights and obligations in the complex legal environment. The situation is more complex when languages and time versions of regulations should be considered. To propose a solution to these demands, we present a semantic enrichment approach which aims at (1) decreasing the ambiguousness of legal texts, (2) increasing the probability of finding the relevant legal materials, and (3) utilizing the application of legal reasoners. Our approach is also implemented both as a service for citizens and businesses and as a modeling environment for legal drafters. To evaluate the usefulness of the approach, a case study was carried out in a large organization and applied to corporate regulations and Hungarian laws. The results suggest this approach can support the previous aims. 相似文献
994.
This paper estimates response surface coefficients for a large range of quantiles of the cross-sectionally augmented IPS (CIPS) test of Pesaran (2007), for different specifications of the deterministic components. An Excel programme is available to calculate the P value associated with a CIPS test statistic. 相似文献
995.
While the analytical philosophy of science regards inconsistent theories as disastrous, Chomsky allows for the temporary tolerance of inconsistency between the hypotheses and the data. However, in linguistics there seem to be several types of inconsistency. The present paper aims at the development of a novel metatheoretical framework which provides tools for the representation and evaluation of inconsistencies in linguistic theories. The metatheoretical model relies on a system of paraconsistent logic and distinguishes between strong and weak inconsistency. Strong inconsistency is destructive in that it leads to logical chaos. In contrast, weak inconsistency may be constructive, because it is capable of accounting for the simultaneous presence of seemingly incompatible structures. However, paraconsistent logic cannot grasp the dynamism of the emergence and resolution of weak inconsistencies. Therefore, the metatheoretical approach is extended to plausible argumentation. The workability of this metatheoretical model is tested with the help of a detailed case study on an analysis of discontinuous constituents in Government-Binding Theory. 相似文献
996.
Andrés Faíña Francisco Bellas Fernando López-Peña Richard J. Duro 《Engineering Applications of Artificial Intelligence》2013,26(10):2408-2423
This paper is devoted to the problem of automatically designing feasible and manufacturable robots made up of heterogeneous modules. Specifically, the coevolution of morphology and control in robots is analyzed and a particular strategy to address this problem is contemplated. To this end, the main issues of this approach such as encoding, evaluation or transfer to reality are studied through the use of heterogeneous modular structures with distributed control. We also propose a constructive evolutionary algorithm based on tree-like representations of the morphology that can intrinsically provide for a type of generative evolutionary approach. The algorithm introduces some new elements to smooth the search space and make finding solutions much easier. The evaluation of the individuals is carried out in simulations and then transferred to real robots assembled from the modules considered. To this end, the extension of the principles proposed by classical authors in traditional evolutionary robotics to brain–body evolution regarding how simulations should be set up so that robust behaviors that can be transferred to reality are obtained is considered here. All these issues are analyzed by means of an evolutionary design system called EDHMoR (Evolutionary Designer of Heterogeneous Modular Robots) that contains all the elements involved in this process. To show practical evidences of the conclusions that have been extracted with this work, two benchmark problems in modular robotics are considered and EDHMoR is tested over them. The first one is focused on solving a linear robot motion mission and the second one on a static task of the robot that does not require displacements. 相似文献
997.
Damaris Fuentes-Lorenzo Norberto Fernández Jesús A. Fisteus Luis Sánchez 《Expert systems with applications》2013,40(6):2287-2296
Traditional search engines have become the most useful tools to search the World Wide Web. Even though they are good for certain search tasks, they may be less effective for others, such as satisfying ambiguous or synonym queries. In this paper, we propose an algorithm that, with the help of Wikipedia and collaborative semantic annotations, improves the quality of web search engines in the ranking of returned results. Our work is supported by (1) the logs generated after query searching, (2) semantic annotations of queries and (3) semantic annotations of web pages. The algorithm makes use of this information to elaborate an appropriate ranking. To validate our approach we have implemented a system that can apply the algorithm to a particular search engine. Evaluation results show that the number of relevant web resources obtained after executing a query with the algorithm is higher than the one obtained without it. 相似文献
998.
Laguzet Florence Romero Andres Gouiffès Michèle Lacassagne Lionel Etiemble Daniel 《Journal of Real-Time Image Processing》2015,10(2):403-422
Journal of Real-Time Image Processing - The paper proposes contributions for mean-shift (MS) and covariance tracking (CT), and makes these two complementary methods cooperate. While MS runs fast... 相似文献
999.
1000.
Younés Abbassi Youcef Ait-Amirat Rachid Outbib 《International journal of systems science》2013,44(16):2873-2886
This paper mainly studies nonlinear feedback control applied to the nonlinear vehicle dynamics with varying velocity. The main objective of this study is the stabilisation of longitudinal, lateral and yaw angular vehicle velocities. To this end, a nonlinear vehicle model is developed which takes both the lateral and longitudinal vehicle dynamics into account. Based on this model, a method to build a nonlinear state feedback control is first designed by which the complexity of system structure can be simplified. The obtained system is then synthesised by the combined Lyapunov–LaSalle method. The simulation results show that the proposed control can improve stability and comfort of vehicle driving. Moreover, this paper presents a lemma which ensures the trajectory tracking and path-following problem for vehicle. It can also be exploited simultaneously to solve both the tracking and path-following control problems of the vehicle ride and driving stability. We also show how the results of the lemma can be applied to solve the path-following problem, in which the vehicle converges and follows a designed path. The effectiveness of the proposed lemma for trajectory tracking is clearly demonstrated by simulation results. 相似文献