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41.
Issa Yavari Manijeh Nematpour Sima Yavari Fatemeh Sadeghizadeh 《Tetrahedron letters》2012,53(15):1889-1890
Ketenimine intermediates generated by the addition of copper acetylides to sulfonyl azides are trapped by nitrile imines (generated from hydrazonoyl chlorides and triethylamine) to afford tetrasubstituted pyrazoles in moderate to good yields. 相似文献
42.
Octavian Sima 《Radiation measurements》2001,34(1-6):181-186
A Monte Carlo based software for the computation of the sensitivity of etched radon track detectors was developed. It can be applied to the measurement of radon and radon daughters in free air or inside of a measurement chamber. LR 115 and CR-39 detectors, with or without an attenuator, are specifically addressed. Various etching conditions and observation criteria for counting the track density may be specified. The latent track formation and the etching process are realistically modelled. The dependence of the etch-rate ratio on the energy is taken into account. The plate-out phenomenon is included in the model. An inhomogeneous source distribution in the detector cup can be considered. 相似文献
43.
We investigate the application of core problem formulations to the context of ill-posed linear algebraic systems. We note that in order to impose regularization on such systems by using core formulations, one is lead to a technique similar to the Truncated (Total) Least Squares method. Choosing an appropriate truncation level from given data can be made efficient by incorporating the truncation level decision as a stopping criterion into a partial bidiagonalization algorithm. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
44.
In recent years, SiC has received increased attention because of its potential for a wide variety of high temperature, high power, high frequency, and/or radiation hardened applications under which conventional semiconductors cannot adequately perform. For semiconductor devices designed to operate in these harsh conditions, SiC offers an unmatched combination of electronic and physical properties. The availability of SiC wafers on a commercial basis has led to the demonstration of many types of metal-oxide semiconductor (MOS)-gated devices that exploit its unique properties. To which extent the potential of SiC power MOSFET can be utilized is a question of appropriate SiC polytype, device structure, MOS interface quality and maturity of the technology. This paper reviews the present status of the SiC power MOSFETs technology that is approaching commercialization. Emphasis is placed upon the impact of SiO2–SiC interface quality on the performance of SiC MOSFETs. 相似文献
45.
Khazali Azadeh Sobhi-Givi Sima Kalbkhani Hashem Shayesteh Mahrokh G. 《Wireless Networks》2020,26(1):253-267
Wireless Networks - Heterogeneous networks (HetNets) provide the demand for high data rates. In this study, we analyze the coexistence of femtocells and device-to-device (D2D) communication with... 相似文献
46.
Abstract— We measured 6β-cholesterol hydroperoxide (6β-CHP), a specific singlet-oxygen (O2 (δg)) product, during irradiation of unilamellar dimyristoyl 1-α-phosphatidylcholine liposomes containing cholesterol and zinc phthalocyanine (ZnPC). The effects of liposome size, the hydrophobic (O2 (1 δg )) quencher, β-carotene, and hydrophilic O2 (1 δg ) quenchers upon the amount of 6β-CHP formed were determined and interpreted in terms of a one dimensional model of 2 (1 δg ) quenching and diffusion. The model correctly predicted (1) that the amount of 6β-CHP was increased with increasing liposome size, (2) that P-carotene was more effective at reducing 6β-CHP formation in 400 nm diameter liposomes than 100 nm diameter liposomes and (3) that the hydrophilic quencher, water, was also more effective in large liposomes than in small liposomes.
The hydrophobic quencher, β-carotene, was more effective at reducing the formation of 6β-CHP than at reducing the 1270 nm O2 (1 δg ) emission. This difference was found to be due to the size distribution present in the liposome preparations because the difference between the 6β-CHP data and the 1270 nm emission data was much smaller in liposome preparations with a narrow size distribution. When a significant size distribution was present, the 6β-CHP data were weighted more heavily with large-diameter liposomes, while the 1270 nm emission data were weighted more heavily with small-diameter liposomes. 相似文献
The hydrophobic quencher, β-carotene, was more effective at reducing the formation of 6β-CHP than at reducing the 1270 nm O
47.
48.
Roya Azad Abolfazl Bezaatpour Mandana Amiri Habibollah Eskandari Sima Nouhi Dereje H. Taffa Michael Wark Rabah Boukherroub Sabine Szunerits 《应用有机金属化学》2019,33(9)
A novel heterogeneous composite material based on reduced graphene oxide (rGO) and bismuth vanadate (BiVO4) was prepared and characterized by various techniques such as powder XRD, HRTEM, EADX, UV–Vis‐DRS, FT‐IR, Raman, BET and XPS analyses. The characterization results reveal that the rGO well decorated by BiVO4. The electrochemical impedance spectroscopy (EIS) shows the increasing of charge transfer of rGO/BiVO4 in presence of light irradiation. In this research, the pure BiVO4 and rGO/BiVO4 composite have been explored for photocatalytic reduction of nitroarenes. Among the prepared nanocomposites, rGO loaded with 10% BiVO4 catalyst (noted as rGO/BiVO4–10%) shows the best performance for the photo‐reduction of various nitroaromatic molecules to their corresponding amine compounds under visible‐light irradiation at room temperature. The catalyst exhibited in particular excellent photocatalytic activity for the conversion of 1,4‐dinitrobenzene to 4‐nitroanilline (100% conversion) in 20 min, 4‐chloronitrobenzene to 4‐chloroaniline and 2‐nitrophenol to 2‐aminophenol (100% conversion) in only 30 min. In addition, the conversion of 4‐bromonitrobenzene, 4‐iodonitrobenzene to their corresponding amine compounds (100% conversion) was achieved in 60 min. The catalyst was recovered for several times and reused without decreasing of its efficiency. 相似文献
49.
Rezayati Sobhan Jafroudi Mogharab Torabi Nezhad Eshagh Rezaee Hajinasiri Rahimeh Abbaspour Sima 《Research on Chemical Intermediates》2016,42(6):5887-5898
Research on Chemical Intermediates - An efficient and cost-effective procedure for preparation of Fe3O4 nanoparticles and supported Brønsted acidic ionic liquid... 相似文献
50.
Murugappan Senthilvelan Mihai Sima Daniel Iancu Michael Schulte John Glossner 《Journal of Signal Processing Systems》2013,70(3):289-303
Emerging wireless applications consistently demand higher data rates. Unfortunately, it is challenging to achieve high data rates within the limited amount of available frequency spectrum. Hence, enhanced spectral efficiency and link reliability within the available frequency spectrum are of the utmost importance in current and next generation wireless protocols. To attain high spectral efficiency and link reliability, wireless protocols employ increasingly complex 2-dimensional techniques that involve computationally-intensive matrix operations. Multiple-Input Multiple-Output (MIMO) communication is an example of a promising technique employed by wireless protocols to deliver higher data rates at the cost of increased algorithmic complexity. Application Specific Integrated Circuits (ASICs) have traditionally been used to implement compute-intensive wireless protocols. The wireless industry has been gradually moving towards an alternative programmable platform called Software Defined Radio (SDR) due to its significant benefits, such as reduced development costs, and accelerated time-to-market. The computationally-intensive matrix operations used in current and next generation wireless protocols are extremely expensive to implement in SDR platforms with conventional Digital Signal Processor (DSP) instruction sets. Hence there is a need for novel instructions, hardware designs and algorithm enhancements to enable higher spectral efficiency on SDR platforms. In this paper, we propose Single Instruction Multiple Data (SIMD) CoOrdinate Rotation DIgital Computer (CORDIC) instruction set extensions with CORDIC hardware support to speedup computationally-intensive matrix decomposition algorithms. The CORDIC instruction set extensions have been implemented on the Sandbridge Sandblaster SB3000 SDR platform and evaluated on conventional algorithms used for decomposing a closed loop 4-by-4 Worldwide Interoperability for Microwave Access (WiMAX) MIMO channel into independent Single-Input Single-Output (SISO) channels. Our experimental results on the closed-loop MIMO channel decomposition using CORDIC instructions demonstrate more than 6x speedup over a Sandblaster baseline implementation that uses state-of-the-art SIMD DSP instructions. The CORDIC instructions also provide similar numerical accuracy when compared to the baseline implementation. The techniques we propose in this paper are also applicable to other SDR and embedded processor architectures. 相似文献