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21.
The problem of stabilizing multiple independent linear systems sharing one conmmon network cable is presented and solved. Both the quanfization and time sequencing are studied in the field of control over networks by providing the formulated stabilizing sufficient condition which illustrates the relationship between the system instability, quanfization and time sequencing, and the data rate is also presented in temps of the quanfization and time sequencing. A numerical example is given to illustrate the result. 相似文献
22.
On neuro-wavelet modeling 总被引:1,自引:0,他引:1
We survey a number of applications of the wavelet transform in time series prediction. The Haar à trous wavelet transform is proposed as a means of handling time series data when future data is unknown. Results are exemplified on financial futures and S&P500 data. Nonlinear and linear multiresolution autoregressionmodels are studied. Experimentally, we show that multiresolution approaches can outperform the traditional single resolution approach to modeling and prediction. 相似文献
23.
K. Strom A. N. Papanicolaou N. Evangelopoulos M. Odeh 《Canadian Metallurgical Quarterly》2004,130(6):554-567
This research aims to advance current knowledge on cluster formation and evolution by tackling some of the aspects associated with cluster microtopography and the effects of clusters on bedload transport. The specific objectives of the study are (1) to identify the bed shear stress range in which clusters form and disintegrate, (2) to quantitatively describe the spacing characteristics and orientation of clusters with respect to flow characteristics, (3) to quantify the effects clusters have on the mean bedload rate, and (4) to assess the effects of clusters on the pulsating nature of bedload. In order to meet the objectives of this study, two main experimental scenarios, namely, Test Series A and B (20 experiments overall) are considered in a laboratory flume under well-controlled conditions. Series A tests are performed to address objectives (1) and (2) while Series B is designed to meet objectives (3) and (4). Results show that cluster microforms develop in uniform sediment at 1.25 to 2 times the Shields parameter of an individual particle and start disintegrating at about 2.25 times the Shields parameter. It is found that during an unsteady flow event, effects of clusters on bedload transport rate can be classified in three different phases: a sink phase where clusters absorb incoming sediment, a neutral phase where clusters do not affect bedload, and a source phase where clusters release particles. Clusters also increase the magnitude of the fluctuations in bedload transport rate, showing that clusters amplify the unsteady nature of bedload transport. A fourth-order autoregressive, autoregressive integrated moving average model is employed to describe the time series of bedload and provide a predictive formula for predicting bedload at different periods. Finally, a change-point analysis enhanced with a binary segmentation procedure is performed to identify the abrupt changes in the bedload statistic characteristics due to the effects of clusters and detect the different phases in bedload time series using probability theory. The analysis verifies the experimental findings that three phases are detected in the bedload rate time series structure, namely, sink, neutral, and source. 相似文献
24.
M. Carroll Author Vitae Author Vitae 《Computers & Electrical Engineering》2004,30(5):331-345
The paper reports on the experiments undertaken at the University of Wollongong to characterise fading profiles and delay parameters of an indoor wireless channels at 5 GHz U-NII bands. The measurements were undertaken at different locations around the campus with results recorded for a post-processing to calculate the Rician K-factor, the level crossing rate and the average fade duration as well as mean excess delay, rms delay spread, and the coherence bandwidth of the channel. The presented measurement results can be useful in developing a Markov chain based model of the transport channel for IEEE802.11a or HYPRLAN-2 networks. The results also indicate scenarios where the coherence bandwidth of the channel is smaller than the width of the sub-carrier OFDM channels in either of the mentioned systems. 相似文献
25.
For developing the X-ray Free Electron Lasers test facility(SXFEL) at Shanghai Institute of Applied Physics,Chinese Academy of Sciences(SINAP), ultra-short bunch is the crucial requirement for excellent lasing performance. It is a big challenge for deflecting cavity to measure the length of ultra-short bunch, and higher deflecting gradient is required for higher measurement resolution. X-band travelling wave deflecting structure has features of higher deflecting voltage and compact structure, which has good performance at ultra-short bunch length measurement. In this paper, a new X-band deflecting structure is designed to operate in HEM11-2π/3 mode.For suppressing the polarization of deflecting plane of the HEM11 mode, two symmetrical caves are added on the cavity wall to separate two polarized modes. 相似文献
26.
对无线信号到达时间(TOA)和到达角度(AOA)的精确估计是室内无线定位的关键。正交频分复用(OFDM)是适合多径衰落环境的一种高速传输技术。提出一种联合TOA和DOA的二维定位方法用于OFDM信号定位。算法首先通过信道估计得到信道的频率响应(CFR),对CFR采用超分辨率算法估计信道时延。首径(first arrival path,FAP)的时延估计就是接收信号的TOA估计。将天线阵列接收信号通过DFT变换到频域,利用同样的算法估计信号各径的AOA/DOA。最后联合TOA和AOA在二维平面上确定目标位置。由于信号是多径、多载波信号,对各载波的DOA/AOA估计在载波间进行处理,再结合各径脉冲响应的幅值,选出属于首径的DOA/AOA估计。在多径环境下仿真表明算法有效且定位精度能够满足实际需要,尤其适合环境中只有一个基站或接入点的情况。 相似文献
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29.
最少时间最小费用路问题的修改Dijkstra算法 总被引:2,自引:0,他引:2
针对同时带有顶点权和弧权的运输网络的最少时间最小费用路问题,首先将该网络转化为一般的只带弧权的运输网络,然后设计了求解该类问题的修改的“带前点标号的Dijkstra算法”,最后给出在物资公路运输中的一个实例。 相似文献
30.
针对现有手势识别算法中存在的计算量复杂、识别率低和效率差等不足,提出一种基于L-ADTW的移动终端手势识别的匹配方法,利用手机内置加速度传感器进行手势识别,采用差分检测方法自动检测出有效手势序列,用改进的起始松弛点对有效手势序列进行校准,使用L-ADTW匹配算法进行有效手势序列段匹配,并将匹配结果与优化阈值比较分析。实验结果表明,提出的L-ADTW算法,在保证手势匹配高效的前提下,使等错率降到2.5%,认证成功率提高了5.37%。 相似文献