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31.
Most modulated signals are cyclostationary, which results in redundancy in the signal frequency spectrum. In this paper, the spectral redundancy which exists in Code Division Multiple Access (CDMA) signals is used in the receiver to improve performance. In particular, we employ a Frequency Shift-Decision Feedback Equalizer (FRESH-DFE) to exploit the cyclostationary. We show that FRESH-DFE is superior to conventional DFE in multiple access CDMA systems, including long code systems. 相似文献
32.
路径干扰是无线传感器网络中的一个关键问题,干扰不但增加了信道竞争,而且会浪费宝贵的能量资源.文章利用现有radio的多频特性,提出了一个干扰避免的频段分配算法IAFA.IAFA根据可用的频段数量,将sink周围的不同区域进行划分,为每个区域指派不同的频段,位于特定区域的节点只能使用相应的频段进行通信,有效地降低了传输路径之间的干扰.此外,文章还基于IAFA给出了具体的路径构建和维护策略.详细的模拟试验验证了IAFA的性能. 相似文献
33.
可编程控制波长调谐的环形掺铒光纤激光器 总被引:3,自引:1,他引:3
提出了一种新型的可调谐光纤激光器,器件采用介质薄膜干涉滤波器进行波长可编程调谐,调谐范围超过38 nm(1 526.5~1 564.6 nm),中心波长可精确调谐到C波段指定的ITU-T波长栅格的标准中心波长处,3 dB带宽小于0.08 nm,25 dB带宽小于0.22 nm,波长稳定性优于0.01 nm,边模抑制比大于60 dB,最大输出光功率35.6 mW,功率稳定性优于±0.02 dB,阈值泵浦功率和斜率效率分别为5.8 mW和36.6%. 相似文献
34.
35.
对下一代移动通信系统的小区间动态干扰协调算法进行研究,通过分析干扰水平,负载状况,基站的调节能力以及用户的位置,通过负载因子变化来接纳控制,提高边缘用户的数据传输速度,保证小区用户的公平性。通过上行功率控制及接纳算法改进方案;同时对小区用户划分区域设定,提出了小区间干扰协调的改进算法(ICPF), 并进行系统仿真计算分析,结果表明和以往传统算法相比,系统性能得到有效改进,进一步提高了系统公平性并增加小区边缘用户的吞吐量。 相似文献
36.
基于多模干涉和长周期光纤光栅的温度及折射率同时测量 总被引:3,自引:1,他引:3
基于多模干涉理论和长周期光纤光栅(LPFG)的传感特性,提出了一种单模-多模-单模(SMS)结构与LPFG级联的光纤传感器,实现了温度和折射率的同时测量。实验结果表明,SMS结构的干涉谱和LPFG对温度和折射率具有不同响应灵敏度,其温度灵敏度分别为0.017nm/℃和0.060nm/℃;SMS结构对折射率不敏感,而LPFG的折射率灵敏度为-35.60nm/RIU(RIU为折射率单位)。因此利用敏感矩阵,实现对温度和折射率的同时测量,得到温度和折射率的最大测量误差分别为±0.59℃和±0.0013。该结构灵敏度高、结构简单,且不易受电磁等干扰。实验结果具有良好的线性度,在生物化学领域应用前景良好。 相似文献
37.
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39.
Volkan?KursunEmail author Siva?G.?Narendra Vivek?K.?De Eby?G.?Friedman 《Analog Integrated Circuits and Signal Processing》2005,44(3):231-238
A CMOS OTA-C low-pass notch filter for EEG application is described. The pass-band covers four bands of brain wave and provides
more than 65 dB attenuation for the 50 Hz power line interference. The OTA works in the weak inversion region and a low transconductance
of 3 nA/V is achieved. The low transconductance enables using small capacitors in the OTA-C filter so that the filter is suitable
for the multi-channel EEG integrated circuits. The measured results show the good performance of the filter for filtering
the noise in acquired EEG signals.
Xinbo Qian received the B.Sc. degree from Beijing Institute of Technology, P.R. China, in 1991 and M.Sc. degree from Institute of Physics,
Chinese Academy of Sciences, in 1996. From 1996 to 1999, she was a research engineer in the Institute of Acoustics, Chinese
Academy of Sciences, worked on the sonar signal receiving and processing systems. Since 1999, she has been pursuing the Ph.D.
degree in Electrical and Computer Engineering department, National University of Singapore, with research direction on on-chip
readout circuits for microbolometer focal plane arrays. Now she is employed by Department of Mechanical Engineering and Division
of Bioengineering, National University of Singapore as a research fellow. Her research interest is low-noise integrated circuits
design and bio-medical sensor electronics, including electroencephalography IC, magnetocardiography IC, low-noise amplifier,
filter and data converters etc.
Yong Ping Xu graduated from Nanjing University, P.R. China in 1977. He received his Ph.D. from University of New South Wales (UNSW) Australia,
in 1994. From 1978 to 1987, he was with Qingdao Semiconductor Research Institute, P.R. China, initially as an IC design engineer,
and later the deputy R&D manager and the Director. From 1989 to 1992, he was working on silicon diode based infrared detectors
towards his Ph.D. at School of Electrical Engineering, UNSW Australia. From 1993 to 1995, he worked on an industry collaboration
project with GEC Marconi, Sydney, Australia, at the same university, involved in design of sigma-delta ADCs. He was a lecturer
at University of South Australia, Adelaide, Australia from 1996 to 1998. He has been with the Department of Electrical and
Computer Engineering, National University of Singapore since June 1998 and is now an Associate Professor. His general research
interests are in the areas of mixed-signal and RF integrated circuits, and integrated MEMS and sensing systems. His current
focuses are high-speed wideband ADC, UWB front-end circuits and low-power low-voltage integrated circuits for biomedical applications.
He is a Senior Member of IEEE.
Xiaoping Li received his Ph.D. degree from Department of Mechanical and Manufacturing Engineering, University of New South Wales, Australia
in 1991, and joined the National University of Singapore in 1992, where he is currently an Associate Professor with the Department
of Mechanical Engineering and Division of Bioengineering. He was a visiting professor of Tokyo Institute of Technology, Japan
in 2000, and visiting professor of Georgia Institute of Technology, USA in 2001. He is a member of American Society of Mechanical
Engineers (ASME), a senior member of Society of Manufacturing Engineering (SME) and a senior member of North American Manufacturing
Research Institute/SME, and is currently the Chairman of SME Singapore Chapter. His current research interests include neurosensors
and nanomachining. He is a guest editor of International Journal of Computer Applications in Technology, USA. He is a regular
reviewer of the ASME Journal of Manufacturing Engineering, USA, Transactions of NAMRI/SME, USA, Journal of materials processing
technology, UK, International Journal of Machine Tools and Manufacture, UK, and IMechE Journal of Engineering Manufacture,
UK. 相似文献
40.
目前逆合成孔径雷达(ISAR)在军事上的作用越来越突出,是目标分类、辨识和战场上敌我识别以及精确制导强有力的手段,在未来防空和导弹防御系统中具有十分重要的作用。本文分析了ISAR成像原理,建立了ISAR系统的仿真模型,并在此基础上对几种干扰技术进行了仿真。 相似文献