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排序方式: 共有520条查询结果,搜索用时 15 毫秒
51.
Dehkordi VR Daou H Labeau F 《IEEE transactions on information technology in biomedicine》2011,15(6):831-838
In this paper, a method is proposed to compress multichannel electroencephalographic (EEG) signals in a scalable fashion. Correlation between EEG channels is exploited through clustering using a k-means method. Representative channels for each of the clusters are encoded individually while other channels are encoded differentially, i.e., with respect to their respective cluster representatives. The compression is performed using the embedded zero-tree wavelet encoding adapted to 1-D signals. Simulations show that the scalable features of the scheme lead to a flexible quality/rate tradeoff, without requiring detailed EEG signal modeling. 相似文献
52.
In this study, alumina nanoparticles and film were synthesized by sol–gel method and thermally grown. The chemical composition, morphology, and structural properties of the grain nanostructures of the nanoaggregate aluminum atoms on the silicon surface are characterized by X-ray diffraction, energy dispersive spectroscopy, and scanning electron microscopy techniques which show that the atomic ratio of Al and O elements is about 60:45 and the mass ratio is about 70:31. This point reveals that there is no intermediate layer between Al2O3 and the silicon substrate. In conclusion, this nanoparticle shows good electron conductivity at the surface of a carbon paste electrode that shows its ability in the preparation of a nanosensor in morphine analysis. The linear response range and detection limit were found to be 0.1–550 and 0.03 μmol L?1, respectively. The proposed sensor was successfully applied for the determination of morphine in real samples such as human urine and drug. 相似文献
53.
Gajski D.D. Vahid F. Narayan S. Jie Gong 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》1998,6(1):84-100
System-level design issues are gaining increasing attention, as behavioral synthesis tools and methodologies mature. We present the SpecSyn system-level design environment, which supports the new specify-explore-refine (SER) design paradigm. This three-step approach to design includes precise specification of system functionality, rapid exploration of numerous system-level design options, and refinement of the specification into one reflecting the chosen option. A system-level design option consists of an allocation of system components, such as standard and custom processors, memories, and buses, and a partitioning of functionality among those components. After refinement, the functionality assigned to each component can then he synthesized to hardware or compiled to software. We describe the issues and approaches for each part of the SpecSyn environment. The new paradigm and environment are expected to lead to a more than ten times reduction in design time, and our experiments support this expectation 相似文献
54.
A new, simple and inexpensive kinetic catalytic spectrophotometric method for the determination of oxalate is described. The method is based on an activation effect of oxalate on a catalytic effect of iron(II) on the oxidation of iodide by bromate. The reaction is monitored by measuring the absorbance of triiodide ion at lambda max = 352 nm. A calibration graph was obtained from 0.10 - 7.0 microg cm(-3) of oxalate with a detection limit of 0.080 microg cm(-3). The standard deviations for ten replicate determinations of 0.50, 1.0 and 5.0 microg cm(-3) of oxalate were 4.0, 2.6 and 1.8%, respectively. The applicability of the method was demonstrated by the determination of oxalate ion in real samples. 相似文献
55.
This paper presents a novel low-power majority function-based 1-bit full adder that uses MOS capacitors (MOSCAP) in its structure. It can work reliably at low supply voltage. In this design, the time-consuming XOR gates are eliminated. The circuits being studied are optimized for energy efficiency at 0.18-μm CMOS process technology. The adder cell is compared with seven widely used adders based on power consumption, speed, power-delay product (PDP) and area efficiency. Intensive simulation runs on a Cadence environment and HSPICE show that the new adder has more than 11% in power savings over a conventional 28-transistor CMOS adder. In addition, it consumes 30% less power than transmission function adder (TFA) and is 1.11 times faster. 相似文献
56.
Lifang Feng Pingzhi Fan Li Hao Kok-keong Loo Vahid Tarokh 《Wireless Personal Communications》2009,50(4):493-507
In this paper, we propose a new construction of signature waveform sets based on Generalized Loosely Synchronization (GLS)
sets and different chip waveforms. The new signature sets are applied into the multi-rate multi-cell quasi-synchronous CDMA
(QS-CDMA) system where each cell is assigned with a GLS set; different users in the same cell are assigned with different
GLS sequences in the same GLS set; user’s different streams are assigned with the same GLS sequence but different chip waveforms.
According to the properties of GLS sets, the inter-cell interference (ICI) and the multi-user interference (MUI) in the same
cell can be reduced significantly. The interferences among different streams of the same user are handled by an optimal (or
suboptimal) multi-stream detector(s), notice that the multi-stream detector mentioned here is also named as multi-user detector
in other references. We compare the performance of the multi-rate multi-cell QS-CDMA system employing the proposed sets with
that of multi-rate system employing well-known concatenated orthogonal/PN sets and that of single-rate system employing GLS
sets. The results show that the multi-rate system employing the proposed sets can achieve significant interference reduction.
Meanwhile the performance of multi-rate system is similar to that of single-rate system due to the inclusion of multi-user
detection.
相似文献
Vahid TarokhEmail: |
57.
The orthogonal frequency-division multiplexing (OFDM) systems are highly sensitive to the nonlinear distortions introduced by the high-power amplifier at the transmitter and to the in-phase and quadrature (IQ) imbalance of the down converter at the receiver. In this paper, the joint effects of these impairments on the performance of the OFDM systems with M signal points quadrature amplitude modulation (M-QAM) are investigated. Moreover, the analytical formulations for the error vector magnitude, the bit error rate, and the total degradation performances of the M-QAM-OFDM systems in additive white Gaussian noise channels as a function of the output back off and IQ imbalance parameters are derived. The computer simulation results confirm the accuracy and validity of our proposed analytical approach. 相似文献
58.
Djafari Rouhani Behzad Mohebbi Vahid 《Journal of Optimization Theory and Applications》2020,186(1):134-147
Journal of Optimization Theory and Applications - By using our own approach, we study the strong convergence of an inexact proximal point algorithm with possible unbounded errors for a maximal... 相似文献
59.
Amir Seirafian Vahid Tabataba Vakily 《International Journal of Communication Systems》2009,22(2):203-217
Exact closed‐form expressions of the Cramer–Rao bound (CRB) for joint sampling clock offset and channel taps are obtained in multi‐carrier code division multiple access systems. CRB is undoubtedly the most well known variance's bound to determine. It provides a benchmark against which we can compare the performance of any unbiased estimator. Furthermore, minimum variance unbiased (MVU) estimator for these parameters is proposed. Moreover, maximum likelihood (ML) and least‐squares estimators for joint sampling clock offset and channel taps are presented. Best linear unbiased estimator is also introduced just for channel taps. The performances of the estimators are compared through simulation results with the proposed CRB. Our results show the better performances of MVU and ML estimators with more computational complexity compared with the others. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
60.
In this paper, we study maximal monotonicity preserving mappings on the Banach space X × X *. Indeed, for a maximal monotone set ${M \subset X\times X^*}$ and for a multifunction ${T: X \times X^* \multimap Y \times Y^*}$ , under some sufficient conditions on M and T we show that T(M) is maximal monotone. As two consequences of this result we get sum and composition rules for maximal monotone operators. 相似文献