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1.
The objective of this review is to organize literature data on the thermodynamic properties of salt‐containing polystyrene/poly(ethylene oxide) (PS/PEO) blends and polystyrene‐b‐poly(ethylene oxide) (SEO) diblock copolymers. These systems are of interest due to their potential to serve as electrolytes in all‐solid rechargeable lithium batteries. Mean‐field theories, developed for pure polymer blends and block copolymers, are used to describe phenomenon seen in salt‐containing systems. An effective Flory–Huggins interaction parameter, χeff , that increases linearly with salt concentration is used to describe the effect of salt addition for both blends and block copolymers. Segregation strength, χeffN , where N is the chain length of the homopolymers or block copolymers, is used to map phase behavior of salty systems as a function of composition. Domain spacing of salt‐containing block copolymers is normalized to account for the effect of copolymer composition using an expression obtained in the weak segregation limit. The phase behavior of salty blends, salty block copolymers, and domain spacings of the latter systems, are presented as a function of chain length, composition and salt concentration on universal plots. While the proposed framework has limitations, the universal plots should serve as a starting point for organizing data from other salt‐containing polymer mixtures. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1177–1187 相似文献
2.
Dr. Mengyi Xiong Dr. Yuting Wu Dr. Gezhi Kong Whitney Lewis Dr. Zhenglin Yang Hanxiao Zhang Li Xu Ying Liu Qin Liu Prof. Xuhua Zhao Prof. Xiao-Bing Zhang Prof. Yi Lu 《Angewandte Chemie (International ed. in English)》2023,62(37):e202308086
DNA-based probes have gained significant attention as versatile tools for biochemical analysis, benefiting from their programmability and biocompatibility. However, most existing DNA-based probes rely on fluorescence as the signal output, which can be problematic due to issues like autofluorescence and scattering when applied in complex biological materials such as living cells or tissues. Herein, we report the development of bioluminescent nucleic acid (bioLUNA) sensors that offer laser excitation-independent and ratiometric imaging of the target in vivo. The system is based on computational modelling and mutagenesis investigations of a genetic fusion between circular permutated Nano-luciferase (NLuc) and HaloTag, enabling the conjugation of the protein with a DNAzyme. In the presence of Zn2+, the DNAzyme sensor releases the fluorophore-labelled strand, leading to a reduction in bioluminescent resonance energy transfer (BRET) between the luciferase and fluorophore. Consequently, this process induces ratiometric changes in the bioluminescent signal. We demonstrated that this bioLUNA sensor enabled imaging of both exogenous Zn2+ in vivo and endogenous Zn2+ efflux in normal epithelial prostate and prostate tumors. This work expands the DNAzyme sensors to using bioluminescence and thus has enriched the toolbox of nucleic acid sensors for a broad range of biomedical applications. 相似文献
3.
Radiation damaged fluorite single crystals iso-thermally annealed showed an oscillating structure of the intensity of a diffracted neutron beam. This is in accord with previous report on crystalline cobaltic compound examined for reconstitution of parent complex ions from recoil hot atoms and for annealing of radiation damage by neutron diffraction. The oscillation phenomenon already found by radiochemical means in various solids irrespectively of their chemical constitution combined by a pure physical method as the neutron diffraction, greatly supports a hypothesis of a spatial temporal oscillatory diffusion of defects in isothermal annealing of radiation damaged crystalline lattice. 相似文献
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5.
In earlier work, a time-dependent, ionization dynamic model of a cluster of xenon atoms was constructed [2], [3] in an effort to determine conditions under which the X-ray line amplification data that was observed experimentally at wavelengths between 2.71 and 2.88 Å [1] could be replicated. Model calculations showed that, at laser intensities greater than 1019 W/cm2, the outermost N-shell electrons of xenon would be stripped away by tunnel ionization in less than a femtosecond. They also showed that L-shell electrons within the resulting cluster of Ni-like ions could be photoionized at a sufficient rate as to generate population inversions between these hole states and the states they radiatively decayed into. These inversions only lasted for several femtoseconds, and they were generated early in time when the cluster was being rapidly heated and the cluster's density was rapidly evolving, but was still high. They were seen to depend on the heating and expansion dynamics of the cluster, which had not been modeled in detail in this early work. In this paper, molecular dynamics calculations are described in which the rapidly evolving temperatures and ion densities of an intensely laser-heated cluster are calculated for different peak laser intensities and for two different sized xenon nano-clusters. This data is then used as an input to the ionization dynamic calculations in order to determine the influence of cluster size and of peak laser intensity on the gain coefficient calculations. In these calculations, inner-shell photoionization rates are shaped by the temperature and density dependence of the bremsstrahlung emissions under the assumption that these emissions drive the photoionizations. This shaping produces calculated gain coefficients that agree well with the measured ones. 相似文献
6.
James B Whitney Saied Mirshahidi So-Yon Lim Lauren Goins Chris C Ibegbu Daniel C Anderson Richard B Raybourne Fred R Frankel Judy Lieberman Ruth M Ruprecht 《Journal of immune based therapies and vaccines》2011,9(1):2
Background
We have evaluated an attenuated Listeria monocytogenes (Lm) candidate vaccine vector in nonhuman primates using a delivery regimen relying solely on oral vaccination. We sought to determine the impact of prior Lm vector exposure on the development of new immune responses against HIV antigens. 相似文献7.
Phi Minh Do Alexander Angerhofer Ivan Hrdy Lucie Bardonova Lonnie O. Ingram K. T. Shanmugam 《Applied biochemistry and biotechnology》2009,153(1-3):21-33
Trichomonas vaginalis generates reduced ferredoxin within a unique subcellular organelle, hydrogenosome that is used as a reductant for H2 production. Pyruvate ferredoxin oxidoreductase and NADH dehydrogenase (NADH-DH) are the two enzymes catalyzing the production of reduced ferredoxin. The genes encoding the two subunits of NADH-DH were cloned and expressed in Escherichia coli. Kinetic properties of the recombinant heterodimer were similar to that of the native enzyme from the hydrogenosome. The recombinant holoenzyme contained 2.15 non-heme iron and 1.95 acid-labile sulfur atoms per heterodimer. The EPR spectrum of the dithionite-reduced protein revealed a [2Fe–2S] cluster with a rhombic symmetry of g xyz?=?1.917, 1.951, and 2.009 corresponding to cluster N1a of the respiratory complex I. Based on the Fe content, absorption spectrum, and the EPR spectrum of the purified small subunit, the [2Fe–2S] cluster was located in the small subunit of the holoenzyme. This recombinant NADH-DH oxidized NADH and reduced low redox potential electron carriers, such as viologen dyes as well as Clostridium ferredoxin that can couple to hydrogenase for H2 production from NADH. These results show that this unique hydrogenosome NADH dehydrogenase with a critical role in H2 evolution in the hydrogenosome can be produced with near-native properties in E. coli for metabolic engineering of the bacterium towards developing a dark fermentation process for conversion of biomass-derived sugars to H2 as an energy source. 相似文献
8.
Gregory B. Kharas Xue Tian Whitney K. Castle Marie B. Cuison Maria R. Fath Bridget Nord 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):355-358
Electrophilic trisubstituted ethylene monomers, ring‐substituted 2‐cyano‐N,N‐dimethyl‐3‐phenyl‐2‐propenamides, RC6H4CH?C(CN)CON(CH3)2 (where R is 4‐(CH3)2N, 4‐CH3CO2, 4‐CH3CONH, 2‐CN, 3‐CN, 4‐CN, 4‐(C2H5)2N) were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and N,N‐dimethyl cyanoacetamide, and characterized by CHN elemental analysis, IR, 1H‐ and 13C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ABCN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C NMR, GPC, DSC, and TGA. High Tg of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 300–450°C range. 相似文献
9.
Patrick Ingram 《Journal of Number Theory》2009,129(1):182-208
If E is a minimal elliptic curve defined over Z, we obtain a bound C, depending only on the global Tamagawa number of E, such that for any point P∈E(Q), nP is integral for at most one value of n>C. As a corollary, we show that if E/Q is a fixed elliptic curve, then for all twists E′ of E of sufficient height, and all torsion-free, rank-one subgroups Γ⊆E′(Q), Γ contains at most 6 integral points. Explicit computations for congruent number curves are included. 相似文献
10.