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31.
Muhammad Aqil Myung-Yung Jeong 《Communications in Nonlinear Science & Numerical Simulation》2012,17(4):1615-1627
This paper addresses dynamic synchronization of two FitzHugh-Nagumo (FHN) systems coupled with gap junctions. All the states of the coupled chaotic system, treating either as single-input or two-input control system, are synchronized by stabilizing their error dynamics, using simplest and locally robust control laws. The local asymptotic stability, chosen by utilizing the local Lipschitz nonlinear property of the model to address additionally the non-failure of the achieved synchronization, is ensured by formulating the matrix inequalities on the basis of Lyapunov stability theory. In the presence of disturbances, it ensures the local uniform ultimate boundedness. Furthermore, the robustness of the proposed methods is ensured against bounded disturbances besides providing the upper bound on disturbances. To the best of our knowledge, this is the computationally simplest solution for synchronization of coupled FHN modeled systems along with unique advantages of less conservative local asymptotic stability of synchronization errors with robustness. Numerical simulations are carried out to successfully validate the proposed control strategies. 相似文献
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A quantum mechanical photodesorption model, valid for metallic substrates and sub-picosecond laser pulses, is presented. It takes into consideration the photodesorption coordinate and models the metal hot-electron mediated desorption by a three electronic states: an ionic state of the adsorbate and two effective states representing the continuum of the metal. This multiple-state picture allows the sharing of the flow of energy injected by the laser between the adsorbate and the substrate. For the first time, the present modeling introduces the hot electrons of the metal through an optical potential based on the kinetic model developed earlier by the authors. This potential, and the resulting desorption yield, depend on the laser fluence. For CO on Cu(1 0 0) or Cu(1 1 1), the results are in fair agreement with the experimental findings. 相似文献
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35.
Optical and magnetic resonance spectroscopy is widely used in the investigation of radiation-induced processes in wide-gap solids. This paper discusses the present understanding of applications of the experimental methods of optical and thermoactivation spectroscopy in the research of new materials, for applications in radiation dosimetry and digital imaging and in the basic research into the fundamental physics and chemistry of radiation. The advantages of the simultaneous use of optical and magnetic resonance techniques for the investigation of stimulated processes are considered. 相似文献
36.
Injection of tunneling electrons and holes from the probe tips of a scanning tunneling microscope was found to enhance the hopping motion of Cl atoms between neighboring dangling-bond sites of Si dimers on Si(1 0 0)-(2 × 1) surfaces, featured by the rate of hopping linearly dependent on the injection current. The hopping rate formed peaks at sample biases of VS∼+1.25 and −0.85 V, which agree with the peaks in the local density of states spectrum measured by scanning tunneling spectroscopy. The Cl hopping was enhanced at Cl-adsorbed sites even remote from the injection point. The Cl hopping by hole injection was more efficiently enhanced by sweeping the tip along the Si dimer row than by tip-sweeping along the perpendicular direction. Such anisotropy, on the other hand, was insignificant in the electron injection case. All of these findings can be interpreted by the model that the holes injected primarily into a surface band originated from the dangling bonds of Si dimers propagate quite anisotropically along the surface, and become localized at Cl sites somehow to destabilize the Si-Cl bonds causing hopping of the Cl atoms. The electrons injected into a bulk band propagate in an isotropic manner and then get resonantly trapped at Si-Cl antibonding orbitals, resulting in bond destabilization and hopping of the Cl atoms. 相似文献
37.
The accumulation of phytoalexin in cucumber plant after stress 总被引:1,自引:0,他引:1
During the course of pathogens penetrating the plant cell, besides of chemical secretion, the pathogens may cause mechanical signal by the physical pressure on the plant cell. In the current study, we use the pressure as the stress signal to study the induction in plant resistance and the effect of accumulation of phytoalexin. We found that stress can induce the resistance in cucumber seeding significantly. Peptides contained RGD motif can specific block the adhesion between plant cell wall and plasma membrane. When breaking the plant cell wall and plasma membrane by using RGD peptides, the stress induction effect is almost absolutely eliminated. The results of assay with TLC and HPLC showed that stress stimulation could increase the accumulation of cucumber seeding phytoalexin. So, we can conclude that the accumulation of phytoalexin is one possible reason of improve the stress induced resistance. When block the adhesion between plant cell wall and plasma membrane by RGD, there are only part of accumulation of phytoalexin. The results suggest that stress induced resistance and accumulation of phytoalexin of plant is required for the adhesion of plant cell wall–plasma membrane. 相似文献
38.
Bochu W Jiping S Biao L Jie L Chuanren D 《Colloids and surfaces. B, Biointerfaces》2004,37(3-4):107-112
Hormones have been suggested to play a prominent role in the control of callus growth. In this paper, with the method of indirect enzyme-linked immunosorbent assays (ELISA), we investigated the induction effect of soundwave on the dynamic change of endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) in vitro during the differentiation process of Chrysanthemum synchronized mature Callus. These experiments showed that groups treated by optimal soundwave (1.4 kHz, 0.095 kdb) had significantly higher IAA levels and lower ABA than that of the control, which had been implicated activation of endogenous IAA and inhibition of ABA. Through the biochemical analysis, it revealed that the increased level of IAA as well as decreased levels of ABA correlated with soundwave stimulus. High rate of IAA/ABA was favorable to development of the callus and differentiation of mature callus. We conclude that soundwave contributes to endogenous hormone as well as the control of callus growth. 相似文献
39.
《中国化学快报》2020,31(5):1141-1146
Non-nerve cell-derived extracellular matrix (ECM) was coated on the aligned porous polypyrrole-poly(l-lactide) (PPy-PLLA) fiber-films with the conductivity of ∼12 mS/m via L929 cells culture and lysing, resulting in ∼10% increase of PC12 cells attachment and ∼26 μm increase of neurites length. The neurite length of ∼149 μm in EGF/NGF group (optimal concentration radio of 12.5/50 (ng/mL)) on aligned and ECM-conjugated fiber-films was significantly larger than ∼94 μm in only NGF group (50 ng/mL), confirming the synergy of EGF, NGF and aligned ECM-conjuaged PPy-PLLA fibers. When differentiated PC12 cells were exerted electrical stimulation (ES) of 100 mV/cm for 4 h/day in 2 day through ECM-PPy-PLLA fiber-films, their neurite length reached to ∼251 μm, significantly larger than ∼149 μm of group without ES, due to the higer expression of related neural proteins in ES group. A simple mechanism was proposed to analyze synergistical effect of ECM, EGF, NGF on axons adhesion and elongation along the aligned ECM-coated fibers under ES condition. 相似文献
40.
Ryosuke NAKANISHI Kosuke TAKEUCHI Kazunori AKIZUKI Ryoma NAKAGOSHI Hironobu KAKIHANA 《Physical Therapy Research》2020,23(2):195
Objective: Neuromuscular electrical stimulation (NMES) has been noted as an effective pre- contraction for an increase of neural and muscle factors during twitch contractions. However, it is unknown if this intervention is effective for the rate of force development (RFD), which is the ability to increase joint torque strength as quickly as possible, during tetanic contractions. NMES can be safely used by anyone, but, the strength setting of NMES requires attention so as not to cause pain. Therefore, the purpose of this study investigated whether NMES at less painful levels was effective for RFD during tetanic contractions. We also investigated effect activation by analyzing electromyogram (EMG) and RFD for each phase. Methods: Eighteen healthy males were studied. Before and after NMES intervention at 10% or 20% maximal voluntary isometric contraction (MVIC) level (10%NMES, 20%NMES respectively), EMG activity and the initial phase (30-, 50-, 100-, and 200-msec) RFD were measured. Visual analog scale (VAS) was also measured as an indicator of pain during each NMES. Results: 20%NMES increased EMG activity and 30-, 50-, and 100-msec of RFD during MVIC, but could not improve 200 msec of RFD. However, 10%NMES could be failed to increase all phases RFD, but VAS was lower than that of 20% NMES. Conclusion: These results suggest that muscle pre-contraction using 20%NMES could induce moderate pain, but could be an effective intervention to improve RFD via neural factor activity. 相似文献