首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6320篇
  免费   325篇
  国内免费   15篇
电工技术   87篇
综合类   10篇
化学工业   1297篇
金属工艺   196篇
机械仪表   322篇
建筑科学   123篇
矿业工程   2篇
能源动力   312篇
轻工业   576篇
水利工程   21篇
石油天然气   8篇
武器工业   1篇
无线电   1076篇
一般工业技术   1288篇
冶金工业   470篇
原子能技术   57篇
自动化技术   814篇
  2024年   11篇
  2023年   83篇
  2022年   118篇
  2021年   208篇
  2020年   160篇
  2019年   151篇
  2018年   182篇
  2017年   181篇
  2016年   213篇
  2015年   191篇
  2014年   303篇
  2013年   413篇
  2012年   438篇
  2011年   473篇
  2010年   351篇
  2009年   337篇
  2008年   373篇
  2007年   281篇
  2006年   227篇
  2005年   217篇
  2004年   184篇
  2003年   160篇
  2002年   147篇
  2001年   116篇
  2000年   111篇
  1999年   110篇
  1998年   202篇
  1997年   136篇
  1996年   120篇
  1995年   76篇
  1994年   54篇
  1993年   59篇
  1992年   31篇
  1991年   24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6660条查询结果,搜索用时 15 毫秒
91.
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   
92.
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   
93.
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   
94.
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   
95.
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   
96.
Zhu  F. Lim  M.S. 《Electronics letters》2004,40(13):811-813
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   
97.
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   
98.
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   
99.
A UV imprint lithography tool has been developed for micro/nano-scale patterning in an extremely large area, i.e., ∼300 × 400 mm2. To achieve high pattern fidelity, residual-layer thickness uniformity, and an air bubble-free layer in a large area, the UV imprint tool has several main components including a silicon rubber uniform pressurizer, a large area UV-LED module, a vacuum pump, a chuck module, etc. Contact and structural analyses have been performed using commercial FEM packages such as LS-DYNA and ANSYS. The developed tool has been tested, and its performance indices including pattern fidelity and residual-layer thickness uniformity have been measured to be ∼97% and ∼90%, respectively.  相似文献   
100.
A lanthanum (La)-doped HfN is investigated as an n-type metal gate electrode on SiO2 with tunable work function. The variation of La concentration in (HfinfinLa1-x)Ny modulates the gate work function from 4.6 to 3.9 eV and remains stable after high-temperature annealing (900degC to 1000degC), which makes it suitable for n-channel MOSFET application. An ultrathin high-fc dielectric layer was formed at the metal/SiO2 interface due to the (HfinfinLa1-x)Ny and SiO2 interaction during annealing. This causes a slight reduction in the effective oxide thickness and improves the tunneling current of the gate dielectric by two to three orders. We also report the tunability of TaN with Al doping, which is suitable for a p-type metal gate work function. Based on our results, several dual-gate integration processes by incorporating lanthanum or aluminum into a refractory metal nitride for CMOS technology are proposed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号