全文获取类型
收费全文 | 99960篇 |
免费 | 8105篇 |
国内免费 | 4287篇 |
专业分类
电工技术 | 5649篇 |
技术理论 | 6篇 |
综合类 | 6272篇 |
化学工业 | 16645篇 |
金属工艺 | 6196篇 |
机械仪表 | 6968篇 |
建筑科学 | 8091篇 |
矿业工程 | 3413篇 |
能源动力 | 2928篇 |
轻工业 | 6323篇 |
水利工程 | 1674篇 |
石油天然气 | 7381篇 |
武器工业 | 809篇 |
无线电 | 10770篇 |
一般工业技术 | 11585篇 |
冶金工业 | 4929篇 |
原子能技术 | 1013篇 |
自动化技术 | 11700篇 |
出版年
2024年 | 458篇 |
2023年 | 1787篇 |
2022年 | 3143篇 |
2021年 | 4295篇 |
2020年 | 3346篇 |
2019年 | 2721篇 |
2018年 | 2925篇 |
2017年 | 3305篇 |
2016年 | 3056篇 |
2015年 | 4132篇 |
2014年 | 4936篇 |
2013年 | 5867篇 |
2012年 | 6328篇 |
2011年 | 6756篇 |
2010年 | 5792篇 |
2009年 | 5539篇 |
2008年 | 5383篇 |
2007年 | 5107篇 |
2006年 | 5432篇 |
2005年 | 4735篇 |
2004年 | 3001篇 |
2003年 | 2839篇 |
2002年 | 2667篇 |
2001年 | 2425篇 |
2000年 | 2341篇 |
1999年 | 2650篇 |
1998年 | 2092篇 |
1997年 | 1740篇 |
1996年 | 1710篇 |
1995年 | 1419篇 |
1994年 | 1163篇 |
1993年 | 739篇 |
1992年 | 649篇 |
1991年 | 438篇 |
1990年 | 353篇 |
1989年 | 301篇 |
1988年 | 228篇 |
1987年 | 150篇 |
1986年 | 122篇 |
1985年 | 70篇 |
1984年 | 53篇 |
1983年 | 44篇 |
1982年 | 41篇 |
1981年 | 28篇 |
1980年 | 25篇 |
1979年 | 16篇 |
1978年 | 1篇 |
1965年 | 1篇 |
1959年 | 2篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Person re-identification receives increasing attentions in computer vision due to its potential applications in video surveillance. In order to alleviate wrong matches caused by misalignment or missing features among cameras, we propose to learn a multi-view gallery of frequently appearing objects in a relatively closed environment. The gallery contains appearance models of these objects from different cameras and viewpoints. The strength of the learned appearance models lies in that they are invariant to viewpoint and illumination changes. To automatically estimate the number of frequently appearing objects in the environment and update their appearance models online, we propose a dynamic gallery learning algorithm. We specifically build up two datasets to validate the effectiveness of our approach in realistic scenarios. Comparisons with benchmark methods demonstrate promising performance in accuracy and efficiency of re-identification. 相似文献
992.
To make full use of the contextual information object recognition and scene understanding, a multi-granular context conditional random field (MGCCRF) model is presented to combine context information in a variety of scales. It is efficiently implemented through extending the pairwise clique to the multi-granular context windows. In the fine-granular context window, the label consistency of similar features can be obtained with the probability of the label transferring between two adjacent pixels. At the same time, the spatial relationships among different classes in the coarse-granular context window are explicated in details. To train the MGCCRF model, a piecewise training method with the bound optimization algorithm is designed to improve the performance. Experiments on two real-world image databases show that compared with other methods, the modified conditional random field model is more competitive and effective in terms of the quantitative and qualitative labeling performance. 相似文献
993.
Lu Zhao Lin Yu-Ru Huang Xiaoxia Xiong Naixue Fang Zhijun 《Multimedia Tools and Applications》2017,76(8):10855-10879
Multimedia Tools and Applications - Nowadays, microblogging has become popular, with hundreds of millions of short messages being posted and shared every minute on a variety of topics in social... 相似文献
994.
Deng Juan Zhao Shu Wang Yan Wang Lei Wang Hong Sha Hong 《Multimedia Tools and Applications》2017,76(7):10097-10117
Multimedia Tools and Applications - Most of the existing image encryption algorithms based on compressive sensing are too complex to operate. An image compression-encryption scheme with simple... 相似文献
995.
The recommendation system is a useful tool that can be employed to identify potential relationships between items and users in electronic commerce systems. Consequently, it can remarkably improve the efficiency of a business. The topic of how to enhance the accuracy of a recommendation has attracted much attention by researchers over the past decade. As such, many methods to accomplish this task have been introduced. However, more complex calculations are normally necessary to achieve a higher accuracy, which is not suitable for a real-time system. Hence, in this paper, we propose a weight-based item recommendation approach to provide a balanced formula between the recommended accuracy and the computational complexity. The proposed methods employ a newly defined distance to describe the relationship between the users and the items, after which the recommendations and predictive algorithms are developed. A data analysis based on the MovieLens datasets indicates that the methods applied can obtain suitable prediction accuracy and maintain a relatively low computational complexity. 相似文献
996.
Consensus clustering is the problem of coordinating clustering information about the same data set coming from different runs of the same algorithm. Consensus clustering is becoming a state-of-the-art approach in an increasing number of applications. However, determining the optimal cluster number is still an open problem. In this paper, we propose a novel consensus clustering algorithm that is based on the Minkowski distance. Fusing with the Newman greedy algorithm in complex networks, the proposed clustering algorithm can automatically set the number of clusters. It is less sensitive to noise and can integrate solutions from multiple samples of data or attributes for processing data in the processing industry. A numerical simulation is also given to demonstrate the effectiveness of the proposed algorithm. Finally, this consensus clustering algorithm is applied to a froth flotation process. 相似文献
997.
Robust Stochastic Stability and
Control for Uncertain Singular Markovian Jump Systems with Multiplicative Noise 下载免费PDF全文
This paper focuses on the problems of robust stability and stabilization and robust control for uncertain singular Markovian jump systems with (x,v)‐dependent noise. The parameter uncertainties appearing in state, input, disturbance as well as diffusion terms are assumed to be time‐varying but norm‐bounded. Based on the approach of generalized quadratic stability, the memoryless state feedback controller is designed for the robust stabilization problem, which ensures that the resulting closed‐loop system has an impulse‐free solution and is asymptotically stable in the mean square. Furthermore, the results of robust control problem are derived. The desired state feedback controller is presented, which not only meets the requirement of robust stabilization but also satisfies a prescribed performance level. The obtained results are formulated in terms of strict LMIs. What we have obtained can be viewed as corresponding extensions of existing results on uncertain singular systems. A numerical example is finally given to demonstrate the application of the proposed method. 相似文献
998.
Hua Zhou Yang Su Rong Wang Yong Zhu Huiping Shen Tao Pu Chuanxin Wu Jiyong Zhao Baofu Zhang Zhiyong Xu 《Quantum Information Processing》2017,16(10):247
Online reconstruction of a time-variant quantum state from the encoding/decoding results of quantum communication is addressed by developing a method of evolution reconstruction from a single measurement record with random time intervals. A time-variant two-dimensional state is reconstructed on the basis of recovering its expectation value functions of three nonorthogonal projectors from a random single measurement record, which is composed from the discarded qubits of the six-state protocol. The simulated results prove that our method is robust to typical metro quantum channels. Our work extends the Fourier-based method of evolution reconstruction from the version for a regular single measurement record with equal time intervals to a unified one, which can be applied to arbitrary single measurement records. The proposed protocol of evolution reconstruction runs concurrently with the one of quantum communication, which can facilitate the online quantum tomography. 相似文献
999.
Lingzhi Zhao Jinde Cao Chengdai Huang Ahmed Alsaedi Abdullah Al-Barakati Habib M. Fardoun 《International Journal of Control, Automation and Systems》2017,15(3):1134-1144
The issue of bifurcation control for a delayed fractional network involving two neurons is concerned. Delay-dependent stability conditions and the bifurcation point are established by discussing the associated characteristic equation of the proposed network. Then, a delayed feedback controller is firstly designed to stabilize the Hopf bifurcation, and desirable dynamics is achieved. It is indicated that the designed controller is extremely effective which can postpone the onset of bifurcation by carefully selecting the feedback gain. Finally, simulation results are given to verify the efficiency of the theoretical results. 相似文献
1000.
A recurrent floating green algae bloom was detected in the Yellow Sea since 2007.The Ulva.prolifera is non\|toxic,but the massive accumulations can result in significant environmental damage and cause economic loss to marine industries.In this study,the spatial and temporal patterns of Ulva.prolifera green tides were investigated in the Yellow Sea during 2015 using HJ\|1A/1B and MODIS satellite images by means of NDVI (normalized difference vegetation index)and artificial interpretation.The results showed:(1)A little Ulva.prolifera was discovered firstly in adjacent sea of Yancheng,Jiangsu province in early May with distribution area 0.831 km2.Under the action of the southeast monsoon,Ulva.prolifera was gradually drifted to Shandong peninsula waters from south to north.The influential area and range reached a peak value with 1 752.756 km2 in late June,and gradually subsided from July to August.And Ulva.prolifera about 38.791 km2 was monitored in the South Bay of North Korea.In conclusion,Ulva.prolifera in the Yellow Sea in 2015 has experienced five major processes including “Occur\|Development\|Outbreak\|Recession\|Disappeared”.(2)Typhoon "CHAN\|HOM" certainly influenced the northward pathway of Ulva.prolifera and shifted towards the southwest,resulting in most of Ulva.prolifera moved to the east coast of Lianyungang,and speculated that minority Ulva.prolifera drifted to the South Bay of North Korea.(3)From the monitoring data,the spatial resolution between MODIS and ENVISAT (HJ\|1A / 1B)is difference significantly,250 m and 30 m respectively.A functional relation of the two data with monitoring area difference about 2.26 times was established to make up for the shortage of the environmental satellite (HJ\|1A/1B)images.
相似文献