全文获取类型
收费全文 | 6431篇 |
免费 | 336篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 89篇 |
综合类 | 15篇 |
化学工业 | 1328篇 |
金属工艺 | 197篇 |
机械仪表 | 324篇 |
建筑科学 | 134篇 |
矿业工程 | 5篇 |
能源动力 | 330篇 |
轻工业 | 581篇 |
水利工程 | 20篇 |
石油天然气 | 23篇 |
武器工业 | 3篇 |
无线电 | 1082篇 |
一般工业技术 | 1297篇 |
冶金工业 | 466篇 |
原子能技术 | 60篇 |
自动化技术 | 826篇 |
出版年
2024年 | 10篇 |
2023年 | 85篇 |
2022年 | 127篇 |
2021年 | 212篇 |
2020年 | 161篇 |
2019年 | 152篇 |
2018年 | 183篇 |
2017年 | 184篇 |
2016年 | 213篇 |
2015年 | 206篇 |
2014年 | 304篇 |
2013年 | 421篇 |
2012年 | 444篇 |
2011年 | 481篇 |
2010年 | 361篇 |
2009年 | 350篇 |
2008年 | 376篇 |
2007年 | 286篇 |
2006年 | 226篇 |
2005年 | 226篇 |
2004年 | 187篇 |
2003年 | 161篇 |
2002年 | 150篇 |
2001年 | 119篇 |
2000年 | 119篇 |
1999年 | 110篇 |
1998年 | 204篇 |
1997年 | 136篇 |
1996年 | 120篇 |
1995年 | 78篇 |
1994年 | 54篇 |
1993年 | 59篇 |
1992年 | 31篇 |
1991年 | 25篇 |
1990年 | 21篇 |
1989年 | 21篇 |
1988年 | 23篇 |
1987年 | 23篇 |
1986年 | 7篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 11篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1974年 | 7篇 |
1972年 | 6篇 |
排序方式: 共有6780条查询结果,搜索用时 14 毫秒
91.
92.
In sensor networks, analyzing power consumption before actual deployment is crucial for maximizing service lifetime. This paper proposes an instruction‐level power estimator (IPEN) for sensor networks. IPEN is an accurate and fine grain power estimation tool, using an instruction‐level simulator. It is independent of the operating system, so many different kinds of sensor node software can be simulated for estimation. We have developed the power model of a Micaz‐compatible mote. The power consumption of the ATmega128L microcontroller is modeled with the base energy cost and the instruction overheads. The CC2420 communication component and other peripherals are modeled according to their operation states. The energy consumption estimation module profiles peripheral accesses and function calls while an application is running. IPEN has shown excellent power estimation accuracy, with less than 5% estimation error compared to real sensor network implementation. With IPEN's high precision instruction‐level energy prediction, users can accurately estimate a sensor network's energy consumption and achieve fine‐grained optimization of their software. 相似文献
93.
Many organisations use decision models in their processes such as tables or trees to provide decision support to their operational
divisions. For example, in fault management, customer contact centre operators usually use a decision model in the form of
prescribed interviews. Based on the answers given by customers, the operator navigates through the decision model to reach
an assessment of the problem. In order to achieve customer satisfaction and operational excellence, it is very important to
constantly monitor the performance of a decision model not only on an overall level, but also on the level of individual decisions.
In this paper we present a configurable business process analytics tool, known as the intelligent Universal Service Management
System, that constantly monitors decision data and is capable of optimising the decisions based on high-level business objectives.
We explain the various features of the software and show how it can be used to optimise decision processes. We also show how
we can easily provide a customised version to monitor the performance of provision processes. 相似文献
94.
Benaissa M. Wei Ming Lim 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2006,14(6):659-662
The design of flexible elliptic curve cryptography processors (ECP) is considered in this paper. Novel word-level algorithms and implementations for the underlying GF(2/sup m/) multiplication and squaring arithmetic which enable improved flexibility versus performance tradeoffs, are presented and employed in the design of an efficient flexible ECP architecture; corresponding field-programmable gate-array (FPGA) prototyping results for two different processor word lengths are also included for evaluation. 相似文献
95.
Baskaya F. Reddy S. Sung Kyu Lim Anderson D.V. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2006,14(8):906-910
Modern advances in reconfigurable analog technologies are allowing field-programmable analog arrays (FPAAs) to dramatically grow in size, flexibility, and usefulness. Our goal in this paper is to develop the first placement algorithm for large-scale floating-gate-based FPAAs with a focus on the minimization of the parasitic effects on interconnects under various device-related constraints. Our FPAA clustering algorithm first groups analog components into a set of clusters so that the total number of routing switches used is minimized and all IO paths are balanced in terms of routing switches used. Our FPAA placement algorithm then maps each cluster to a computational analog block (CAB) of the target FPAA while focusing on routing switch usage and balance again. Experimental results demonstrate the effectiveness of our approach. 相似文献
96.
Joo‐Young Lim Jargalsaikhan Nyambayar Je‐Young Yun Dong‐Hyun Kim Tae‐Hyung Kim Bierng‐Chearl Ahn Jae‐Hoon Bang 《ETRI Journal》2014,36(6):889-893
This paper presents a high‐performance dual‐circularly polarized feed employing a dielectric‐filled circular waveguide. Novel features are incorporated in the proposed feed, such as a dielectric rod radiator for high gain and good impedance matching; dual quarter‐wave chokes for low axial ratio over wide angles and for low back radiation; an integrated septum polarizer; and two end‐launch‐type coaxial‐to‐waveguide transitions. The proposed feed shows excellent performance at 5.0 GHz to 5.2 GHz. 相似文献
97.
Moh Lim Sim Gunawan E. Boon-Hee Soong Cheong-Boon Soh 《Vehicular Technology, IEEE Transactions on》1999,48(3):911-921
Performance of a reverse link code-division multiple-access (CDMA) system with fast close-loop power control algorithms is studied. It is found that if the fast close-loop power control algorithm functions effectively, the speed of the mobile unit is in the range such that its Doppler frequency is less than one tenth of the power control updating rate. This paper also proposes a new predictive power control algorithm with better performance in terms of system capacity than the conventional and adaptive step size algorithms. An increase in system capacity as high as 22% compared with the conventional algorithm can be achieved depending on the mobile velocity 相似文献
98.
The performance of the combined beamforming of space-time block coding according to the number of antenna array groups has been analysed. CB/spl I.bar/STBC/spl I.bar/single array and CB/spl I.bar/STBC/spl I.bar/double array were compared under the condition of DOA and SNR. CB/spl I.bar/STBC/spl I.bar/double array is shown to have a stable performance independent of DOA and angular spread. 相似文献
99.
Seyoon Jeong Sung‐Chang Lim Hahyun Lee Jongho Kim Jin Soo Choi Haechul Choi 《ETRI Journal》2011,33(2):145-154
We present a novel video codec for supporting entertainment‐quality video. It has new coding tools such as an intra prediction with offset, integer sine transform, and enhanced block‐based adaptive loop filter. These tools are used adaptively in the processing of intra prediction, transform, and loop filtering. In our experiments, the proposed codec achieved an average reduction of 13.35% in BD‐rate relative to H.264/AVC for 720p sequences. 相似文献
100.
Chin-Te WangChien-I Kuo Heng-Tung HsuEdward Yi Chang Li-Han HsuWee-Chin Lim Che-Yang ChiangSzu-Ping Tsai Guo-Wei Huang 《Microelectronic Engineering》2011,88(2):183-186
In this paper, we present a flip-chip 80-nm In0.7Ga0.3As MHEMT device on an alumina (Al2O3) substrate with very little decay on device RF performance up to 60 GHz. After package, the device exhibited high IDS = 435 mA/mm at VDS = 1.5 V, high gm = 930 mS/mm at VDS = 1.3 V, the measured gain was 7.5 dB and the minimum noise figure (NFmin) was 2.5 dB at 60 GHz. As compared to the bare chip, the packaged device exhibited very small degradation in performance. The result shows that with proper design of the matching circuits and packaging materials, the flip-chip technology can be used for discrete low noise FET package up to millimeter-wave range. 相似文献