全文获取类型
收费全文 | 206016篇 |
免费 | 15416篇 |
国内免费 | 7812篇 |
专业分类
电工技术 | 11264篇 |
技术理论 | 14篇 |
综合类 | 11236篇 |
化学工业 | 35795篇 |
金属工艺 | 10545篇 |
机械仪表 | 12007篇 |
建筑科学 | 16422篇 |
矿业工程 | 4945篇 |
能源动力 | 5860篇 |
轻工业 | 12710篇 |
水利工程 | 3219篇 |
石油天然气 | 11096篇 |
武器工业 | 1349篇 |
无线电 | 25495篇 |
一般工业技术 | 26731篇 |
冶金工业 | 10939篇 |
原子能技术 | 2124篇 |
自动化技术 | 27493篇 |
出版年
2024年 | 884篇 |
2023年 | 3265篇 |
2022年 | 5836篇 |
2021年 | 7938篇 |
2020年 | 5807篇 |
2019年 | 5019篇 |
2018年 | 5427篇 |
2017年 | 6209篇 |
2016年 | 5699篇 |
2015年 | 7308篇 |
2014年 | 9534篇 |
2013年 | 12289篇 |
2012年 | 12244篇 |
2011年 | 13895篇 |
2010年 | 11625篇 |
2009年 | 11473篇 |
2008年 | 10882篇 |
2007年 | 10472篇 |
2006年 | 10871篇 |
2005年 | 9641篇 |
2004年 | 6574篇 |
2003年 | 5781篇 |
2002年 | 5264篇 |
2001年 | 4733篇 |
2000年 | 4876篇 |
1999年 | 5646篇 |
1998年 | 5288篇 |
1997年 | 4357篇 |
1996年 | 3961篇 |
1995年 | 3317篇 |
1994年 | 2774篇 |
1993年 | 2187篇 |
1992年 | 1701篇 |
1991年 | 1278篇 |
1990年 | 1019篇 |
1989年 | 880篇 |
1988年 | 682篇 |
1987年 | 497篇 |
1986年 | 395篇 |
1985年 | 334篇 |
1984年 | 212篇 |
1983年 | 198篇 |
1982年 | 165篇 |
1981年 | 145篇 |
1980年 | 131篇 |
1979年 | 97篇 |
1978年 | 63篇 |
1977年 | 63篇 |
1976年 | 77篇 |
1975年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Rui-Hong Liang Xian-Lin Dong Ying Chen Fei Cao Yong-Ling Wang 《Journal of the American Ceramic Society》2006,89(10):3273-3276
Ba0.55 Sr0.45 TiO3 /MgO composites were successfully prepared by the heterogeneous precipitation method and their structural, surface morphological, tunable properties, and dielectric properties at microwave frequency were systemically investigated. Compared with the sample prepared by the traditional solid-state method, the sample prepared by the heterogeneous precipitation method exhibits a smaller grain size, more uniform microstructure, higher tunability, and lower microwave loss, and these properties are very beneficial to the development of the microwave tunable devices application. Moreover, the effects of La2 O3 doping on the dielectric and tunable properties of BST/MgO composites are investigated. The result shows that the La3+ -doped sample has higher tunability and lower microwave loss than the undoped one. 相似文献
942.
针对TD-LTE系统中同步性错误随机发生的问题,提出了一种通过ARM+DSP+FPGA平台的嵌入式系统实现帧号和原语的同步校正方法。该方法基于TD-LTE射频一致性测试仪表硬件平台,通过该嵌入式系统中ARM、DSP、FPGA间的协调工作,由GPMC模块通过帧号和原语两方面对系统同步性进行校正。在TD-LTE射频一致性测试仪表硬件平台中进行了验证,结果表明,该方法在实现帧号与子帧号同步校正的基础上明显提高了TD-LTE系统通信的稳定性。 相似文献
943.
944.
945.
946.
Traditional methods based on the product of exponentials (POE) formula are parametrically continuous and complete for the calibration of the kinematic parameters of serial robots. However, these methods are not minimal due to the constraints of joint twists. This paper puts forward a new POE-based model, whose parameters are totally independent and conform to the formula of minimality. This is the first model that simultaneously satisfies the requirements of parametric continuity, completeness, and minimality with uniform and generic modeling rules. The proposed approach avoids the operations of normalization and orthogonalization which are necessary redundancy elimination steps with the traditional model. Simulations on a SCARA robot and experiments on an ABB IRB 120 robot prove that the new model outperforms in convergence, accuracy, and efficiency. 相似文献
947.
Guo-Qiang Chen 《Journal of Polymer Research》2003,10(4):289-290
Volume Contents
Contents Volume 10 (2003) 相似文献948.
We propose a parametric weighting function for weighted ordered weighted averaging (WOWA) operator in decision making under uncertainty and risk environment. The weighting function is not only related to the attitude of the decision makers, but also to the event probability. Under the proposed method, the decision makers underweight small probability gains and overweight large probability gains, which is right in consistence with the psychology of the decision makers in the prospect theory. Meanwhile, it generalizes two specific weighting functions and proposed by Torra (International Journal of Intelligent Systems 12 (1997) 153–166). Moreover, the expected utility becomes a special case of the parametric weighting function for WOWA operator. To illustrate its application, an example of introducing and pricing new product is given, which shows the optimal strategies corresponding to different parameter values r. 相似文献
949.
Parallelizing Complex Streaming Applications on Distributed Scratchpad Memory Multicore Architecture
Shin-Kai Chen Cheng-Yu Hung Ching-Chih Chen Chih-Wei Liu 《International journal of parallel programming》2014,42(6):875-899
Multicore processors can provide sufficient computing power and flexibility for complex streaming applications, such as high-definition video processing. For less hardware complexity and power consumption, the distributed scratchpad memory architecture is considered, instead of the cache memory architecture. However, the distributed design poses new challenges to programming. It is difficult to exploit all available capabilities and achieve maximal throughput, due to the combined complexity of inter-processor communication, synchronization, and workload balancing. In this study, we developed an efficient design flow for parallelizing multimedia applications on a distributed scratchpad memory multicore architecture. An application is first partitioned into streaming components and then mapped onto multicore processors. Various hardware-dependent factors and application-specific characteristics are involved in generating efficient task partitions and allocating resources appropriately. To test and verify the proposed design flow, three popular multimedia applications were implemented: a full-HD motion JPEG decoder, an object detector, and a full-HD H.264/AVC decoder. For demonstration purposes, SONY PlayStation \(^{\circledR }\) 3 was selected as the target platform. Simulation results show that, on PS3, the full-HD motion JPEG decoder with the proposed design flow can decode about 108.9 frames per second (fps) in the 1080p format. The object detection application can perform real-time object detection at 2.84 fps at \(1280 \times 960\) resolution, 11.75 fps at \(640 \times 480\) resolution, and 62.52 fps at \(320 \times 240\) resolution. The full-HD H.264/AVC decoder applications can achieve nearly 50 fps. 相似文献
950.