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71.
We have developed a new method for solving quantum dynamical scattering problems, using the time-independent Schr?dinger equation (TISE), based on a novel method to generalize a "one-way" quantum mechanical wave equation, impose correct boundary conditions, and eliminate exponentially growing closed channel solutions. The approach is readily parallelized to achieve approximate N(2) scaling, where N is the number of coupled equations. The full two-way nature of the TISE is included while propagating the wave function in the scattering variable and the full S-matrix is obtained. The new algorithm is based on a "Modified Cayley" operator splitting approach, generalizing earlier work where the method was applied to the time-dependent Schr?dinger equation. All scattering variable propagation approaches to solving the TISE involve solving a Helmholtz-type equation, and for more than one degree of freedom, these are notoriously ill-behaved, due to the unavoidable presence of exponentially growing contributions to the numerical solution. Traditionally, the method used to eliminate exponential growth has posed a major obstacle to the full parallelization of such propagation algorithms. We stabilize by using the Feshbach projection operator technique to remove all the nonphysical exponentially growing closed channels, while retaining all of the propagating open channel components, as well as exponentially decaying closed channel components. 相似文献
72.
Pratima R. Solanki Ajeet Kaushik Anees A. Ansari G. Sumana B. D. Malhotra 《先进技术聚合物》2011,22(6):903-908
Horse radish peroxidase (HRP) has been electrochemically entrapped into perchlorate (ClO) doped polyaniline (PANI) film deposited onto indium‐tin‐oxide (ITO) coated glass plate. This HRP‐PANI‐ClO/ITO bioelectrode characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), UV‐Visible spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques has been utilized for estimation of hydrogen peroxide (H2O2). This H2O2 sensor exhibits response time of 5 s, linearity from 3 to 136 mM, sensitivity as 0.5638 µA mM?1 cm?2 with linear regression of 0.985. The value of the Michaelis–Menten constant (Km) has been obtained as 1.984 mM. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
73.
Multiresidue analysis of multiclass plant growth regulators in grapes by liquid chromatography/tandem mass spectrometry 总被引:1,自引:0,他引:1
Oulkar DP Banerjee K Ghaste MS Ramteke SD Naik DG Patil SB Jadhav MR Adsule PG 《Journal of AOAC International》2011,94(3):968-977
A selective and rapid multiresidue analysis method is presented for simultaneous estimation of 12 plant growth regulators (PGRs), namely, auxins (indol-3-acetic acid, indol-3-butyric acid, and naphthyl acetic acid), cytokinins (kinetin, zeatin, and 6-benzyladenine), gibberellic acid (GA3), abscisic acid, and synthetic compounds, namely, forchlorfenuron, paclobutrazole, isoprothiolane, and 2,4-dichlorophenoxy acetic acid (2,4-D) in bud sprouts and grape berries at the development stages of 2-3 and 6-8 mm diameters, which are the critical phases when exogenous application of PGRs may be necessary to achieve desired grape quality and yield. The sample preparation method involved extraction of plant material with acidified methanol (50%) by homogenization for 2 min at 15000 rpm. The pH of the extract was enhanced up to 6 by adding ammonium acetate, followed by homogenization and centrifugation. The supernatant extract was cleaned by SPE on an Oasis HLB cartridge (200 mg, 6 cc). The final extract was measured directly by LC/MS/MS with electrospray ionization in positive mode, except for 2,4-D, GA3, and abscisic acid extracts, which required analysis in negative mode. Quantification by multiple reaction monitoring (MRM) was supported with full-scan mass spectrometric confirmation using "information-dependent acquisition" triggered with MRM to "enhanced product ionization" mode of the hybrid quadrupole-ion trap mass analyzer. The LOQ of the test analytes varied between 1 and 10 ng/g with associated recoveries of 80-120% and precision RSD <25% (n = 8). Significant matrix-induced signal suppression was recorded when the responses for pre- and postextraction spikes of analytes were compared; this could be resolved by using matrix-matched calibration standards. The method could successfully be applied in analyzing incurred residue samples and would, therefore, be useful in precisely deciding the necessity and dose of exogenous applications of PGRs on the basis of measured endogenous levels. 相似文献
74.
Goken EG Joshi KL Russo MF van Duin AC Castleman AW 《The journal of physical chemistry. A》2011,115(18):4657-4664
Computational chemistry simulations were performed to determine the effect that the addition of a single formic acid molecule has on the structure and stability of protonated water clusters. Previous experimental studies showed that addition of formic acid to protonated pure water results in higher intensities of large-sized clusters when compared to pure water and methanol-water mixed clusters. For larger, protonated clusters, molecular dynamics simulations were performed on H(+)(H(2)O)(n), H(+)(H(2)O)(n)CH(3)OH, and H(+)(H(2)O)(n)CHOOH clusters, 19-28 molecules in size, using a reactive force field (ReaxFF). Based on these computations, formic acid-water clusters were found to have significantly higher binding energies per molecule. Addition of formic acid to a water cluster was found to alter the structure of the hydrogen-bonding network, creating selective sites within the cluster, enabling the formation of new hydrogen bonds, and increasing both the stability of the cluster and its rate of growth. 相似文献
75.
Yang CW Chanda K Lin PH Wang YN Liao CW Huang MH 《Journal of the American Chemical Society》2011,133(49):19993-20000
By using octahedral gold nanocrystals with sizes of approximately 50 nm as the structure-directing cores for the overgrowth of Pd shells, Au-Pd core-shell heterostructures with systematic shape evolution can be directly synthesized. Core-shell octahedra, truncated octahedra, cuboctahedra, truncated cubes, and concave cubes were produced by progressively decreasing the amount of the gold nanocrystal solution introduced into the reaction mixture containing cetyltrimethylammonium bromide (CTAB), H(2)PdCl(4), and ascorbic acid. The core-shell structure and composition of these nanocrystals has been confirmed. Only the concave cubes are bounded by a variety of high-index facets. This may be a manifestation of the release of lattice strain with their thick shells at the corners. Formation of the [CTA](2)[PdBr(4)] complex species has been identified spectroscopically. Time-dependent UV-vis absorption spectra showed faster Pd source consumption rates in the growth of truncated cubes and concave cubes, while a much slower reduction rate was observed in the generation of octahedra. The concave cubes and octahedra were used as catalysts for a Suzuki coupling reaction. They can all serve as effective and recyclable catalysts, but the concave cubes gave higher product yields with a shorter reaction time attributed to their high-index surface facets. The concave cubes can also catalyze a wide range of Suzuki coupling reactions using aryl iodides and arylboronic acids with electron-donating and -withdrawing substituents. 相似文献
76.
A new chromogenic protocol has been developed for rapid and selective detection of nerve agents like tabun. The chemsensor displayed a drastic color change from its colorless solution to yellow instantaneously with an 89 nm bathochromic shift. No inference of other chemical warfare agents and its mimics was observed either with the naked-eye or by UV-Vis spectroscopy. The development of a portable chemosensor kit for tabun demonstrates its practical application in real-time monitoring. 相似文献
77.
Dasgupta S Banerjee K Utture S Kusari P Wagh S Dhumal K Kolekar S Adsule PG 《Journal of chromatography. A》2011,1218(38):6780-6791
78.
We consider providing presence service for duty-cycled wireless sensor networks through a multihop approach. The presence
service is to ensure automatic network monitoring by which each node would know whether the sink node is reachable or not.
Towards providing such presence service, we tackle three problems: 1) efficient neighbor discovery due to not-always-awake
nature of duty-cycling and the mobile environment, 2) light presence message passing from the sink node to all reachable nodes
given broadcasting is expensive and difficult in an embedded duty-cycling network, and 3) automatic network monitoring if
there is node failure and network partition. In our protocol, in order to save power consumption, an online node which is
reachable from the sink node only book-keeps the broadcast schedule of its parent in a breadth-first-search spanning tree
in order to trace the online status all along. The offline node which is not reachable from the sink node stays awake periodically
based on quorum-based wakeup scheduling, and probes the beacons which may come from online nodes. The presence protocol can
automatically detect link failure or network partition, and it can also automatically recover online status for each sensor
node if there is a path to the sink node, which is significant for applications that are sensitive to end-to-end latency constraints.
The presence protocol proposed is implemented through a layered approach so that it is independent from any specific MAC and
routing protocols. We make extensive simulations in order to validate the energy efficiency and reliability of our design. 相似文献
79.
Galileo Sarasqueta Kaushik Roy Choudhury Jegadesan Subbiah Franky So 《Advanced functional materials》2011,21(1):167-171
A PbSe solution‐processed nanocrystal‐based infrared photodetector incorporating carrier blocking layers is demonstrated, and significant reduction of dark current is achieved. Detectivity values close to 1012 Jones are achieved by using poly[(9,9′‐dioctylfluorenyl‐2,7‐diyl)‐co‐(4,4′‐(N‐(4‐sec‐butyl))diphenylamine)] (TFB) and ZnO nanocrystals (NC) as the electron blocker and hole blocker, respectively. An improvement in lifetime is also observed in the devices with the ZnO NCs hole blocking layer. 相似文献
80.
B. Ravindran G. Madhurambal M. Mariappan K. Ramamurthi S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2011,104(3):909-914
Single crystals of mercury cinnamate were grown by slow evaporation of methanol solution at room temperature. The effect of
mercury on the electronic structure of cinnamic acid was studied. The grown mercury cinnamate single crystals were characterized
by UV, FTIR and TG-DTA. TG curve of mercury cinnamate exhibits higher thermal stability compared with cinnamic acid which
was also confirmed by DTA curve. The spectroscopic studies give evidences of the distribution of the electronic charge in
molecule, the delocalisation of π electrons and the reactivity of metal complexes. The Second harmonic generation efficiency
is more pronounced in the presence of mercury dopant in the growth medium. 相似文献