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111.
Crystalline solid solution of BiHoXFe1+XO3 (X=0, 0.05, 0.1, and 0.15) ceramics have been successfully synthesized by slow step sintering schedule. At particular value of X (X=0.1) the sample showed good crystallinity with almost impurity free phases. It was observed that at particular concentration of X (X=0.1), the sample showed enhanced M–H loop by Ho doping in presence of excess Fe. Furthermore, the M–H loop gets reduced with the increase in value of X (X=0.15). Compared to the pure BFO, the dielectric properties for X=0.1 composition are improved due to the decreased oxygen vacancies by the stabilized oxygen octahedron. Raman spectra over the frequency range of 100–1500 cm?1 have been systematically investigated with different concentrations of X. Besides the changes of the peak position and the line width of the all modes, the prominent frequency shift, the line broadening and variation of the intensity for the two-phonon mode between 1270 and 1280 cm?1 were observed with increase in value of X. All these results indicate the existence of strong spin–phonon coupling in Ho doped Fe rich BFO. 相似文献
112.
We present pulsed laser operation in a Nd-doped, Y3Al5O12-based silica fiber. The fiber was fabricated using the rod-in-tube technique with a Nd:YAG crystal rod as the core material and a silica tube for the cladding material. A spectroscopy study revealed that the core region had become amorphous in the process of fiber drawing. Q-switched pulsed laser operation was realized at a wavelength of 1058 nm when the fiber was cladding pumped at a wavelength of 808 nm. The laser delivered 38 μJ of energy in 65 ns pulses. The extracted energy was limited due to the multimodal operation of the fiber. Laser slope efficiency in continuous wave operation reached 52%. The spectroscopic properties of the fabricated fiber are discussed and compared to a Nd:YAG crystal and a Nd:Al-doped silica fiber. 相似文献
113.
Simple one-step synthesis of highly luminescent carbon dots from orange juice: application as excellent bio-imaging agents 总被引:2,自引:0,他引:2
S Sahu B Behera TK Maiti S Mohapatra 《Chemical communications (Cambridge, England)》2012,48(70):8835-8837
Highly photoluminescent carbon dots with a PL quantum yield of 26% have been prepared in one step by hydrothermal treatment of orange juice. Due to high photostability and low toxicity these carbon dots are demonstrated as excellent probes in cellular imaging. 相似文献
114.
We report cystine-based macrocyclic compounds showing very unique self-assembling behavior. 24-membered disulfide macrocycle 3 shows a helical and tubular organization and also forms an insoluble plaque that is birefringent with congo red dye. 48-membered macrocycle 4 shows a vesicle-like assembly with capability for encapsulation, as demonstrated by rhodamine B encapsulation. 相似文献
115.
Hill JP Subbaiyan NK D'Souza F Xie Y Sahu S Sanchez-Ballester NM Richards GJ Mori T Ariga K 《Chemical communications (Cambridge, England)》2012,48(33):3951-3953
Tetrapyrazinoporphyrazine substituted at its periphery with eight antioxidant 3,5-di-t-butyl-4-hydroxyphenyl groups behaves as a turn-on fluorescent sensor for fluoride anions. Conversely, the precursor antioxidant-substituted 1,2-phthalonitrile was found to act in turn-off mode suggesting that the origin of the phenomenon lies at the phenolate-substituted 1,4-pyrazinyl moiety. 相似文献
116.
S. Meenakshi S. D. Bhat A. K. Sahu S. Alwin P. Sridhar S. Pitchumani 《Journal of Solid State Electrochemistry》2012,16(4):1709-1721
Hybrid dual-network membranes comprising chitosan (CS)–polyvinyl alcohol (PVA) networks crosslinked with sulfosuccinic acid
(SSA) and glutaraldehyde (GA) and modified with stabilized silicotungstic acid (SWA) are reported for their application in
direct methanol fuel cells (DMFCs). Physico-chemical properties of these membranes are evaluated using thermo-gravimetric
analysis and scanning electron microscopy in conjunction with their mechanical properties. Based on water sorption and proton
conductivity measurements for the membranes, the optimum content of 10 wt.% SWA in the membrane is established. The methanol
crossover for these membranes are studied by measuring the mass balance of methanol using density meter and are found to be
lower compared to Nafion-117 membrane. The membrane–electrode assembly with 10 wt.% stabilized SWA–CS–PVA hybrid membrane
with SSA and GA as crosslinking agent delivers a peak power density of 156 mW cm−2 at a load current density of 400 mA cm−2 and 88 mW cm−2 at a load current density of 300 mA cm−2, respectively, in DMFC at 70 °C. 相似文献
117.
The structural properties of Au/TiO2 catalyst were studied by X-ray diffraction, UV-visible diffuse reflectance, photoluminescene, scanning transmission and electron
microscope, and temperature programmed reduction. The photocatalytic activity of the catalysts was evaluated for the degradation
of various azo-dyes such as methylene blue, methyl orange, reactive blue-4, and eosin-B under solar irradiation. It was found
that TiO2 catalyst modified with gold exhibits higher percentage of degradation compared to starting TiO2. For example, TiO2 showed 35% of methyl orange degradation whereas gold modified TiO2 possessed 82%. Effect of different parameters such as pH and dye concentration has been evaluated and the photocatalytic
activity was correlated with physico-chemical properties. The dye degradation rate followed first order kinetics. 相似文献
118.
The lipid mediator Platelet-activating factor (PAF) and oxidized glycerophosphocholine PAF agonists produced by UVB have been demonstrated to play a pivotal role in UVB-mediated systemic immunosuppression. Importantly, employing the ability of distant UVB irradiation to inhibit contact hypersensitivity (CHS) responses to the chemical antigen dinitrofluorobenzene (DNFB) to an area of unirradiated murine skin, we and others have demonstrated that UVB-mediated systemic immunosuppression was only observed in PAF-R expressing wild type (WT) mice and not in PAF-R-knockout (Pafr-/-) mice. As it is not known if PAF is involved in UVB-mediated local immunosuppression, these studies compared local UVB on CHS responses in WT versus Pafr-/- mice. We demonstrate that the application of DNFB onto UVB-exposed (locally) area of mouse skin resulted in a similar significant inhibition of subsequent CHS responses in both WT and Pafr-/- mice compared to sham-irradiated control mice. Furthermore, the expression of langerin, a marker for the presence of Langerhans cells was substantially reduced equally in the epidermal ears of UVB-irradiated WT and Pafr-/- mice compared to their respective sham control groups. These findings indicate that the PAF-R is not involved UVB-induced local immunosuppression. 相似文献
119.
Increasingly large volumes of space–time data are collected everywhere by mobile computing applications, and in many of these cases, temporal data are obtained by registering events, for example, telecommunication or Web traffic data. Having both the spatial and temporal dimensions adds substantial complexity to data analysis and inference tasks. The computational complexity increases rapidly for fitting Bayesian hierarchical models, as such a task involves repeated inversion of large matrices. The primary focus of this paper is on developing space–time autoregressive models under the hierarchical Bayesian setup. To handle large data sets, a recently developed Gaussian predictive process approximation method is extended to include autoregressive terms of latent space–time processes. Specifically, a space–time autoregressive process, supported on a set of a smaller number of knot locations, is spatially interpolated to approximate the original space–time process. The resulting model is specified within a hierarchical Bayesian framework, and Markov chain Monte Carlo techniques are used to make inference. The proposed model is applied for analysing the daily maximum 8‐h average ground level ozone concentration data from 1997 to 2006 from a large study region in the Eastern United States. The developed methods allow accurate spatial prediction of a temporally aggregated ozone summary, known as the primary ozone standard, along with its uncertainty, at any unmonitored location during the study period. Trends in spatial patterns of many features of the posterior predictive distribution of the primary standard, such as the probability of noncompliance with respect to the standard, are obtained and illustrated. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
120.
In this article, the novel (G ′/G)-expansion method is successfully applied to construct the abundant travelling wave solutions to the KdV–mKdV equation with the aid of symbolic computation. This equation is one of the most popular equation in soliton physics and appear in many practical scenarios like thermal pulse, wave propagation of bound particle, etc. The method is reliable and useful, and gives more general exact travelling wave solutions than the existing methods. The solutions obtained are in the form of hyperbolic, trigonometric and rational functions including solitary, singular and periodic solutions which have many potential applications in physical science and engineering. Many of these solutions are new and some have already been constructed. Additionally, the constraint conditions, for the existence of the solutions are also listed. 相似文献