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81.
2,3‐Dimethylpentacene (DMP) and 2,3‐dimethyltetracene (DMT) were synthesized, characterized and employed as the channel material in the fabrication of thin‐film transistors. The two methyl groups increase the chemical stability of the compounds versus the pristine acene analogues. The crystals maintain herringbone‐like molecular packing, whereas the weak dipole associated with the unsymmetrical molecule induces an anti‐parallel alignment among the neighbors. This structural motif favors layered film growth on SiO2/Si surface. Thin film transistors prepared on SiO2/Si and n‐nonyltrichlorosilane‐modified SiO2/Si at different substrate temperatures were compared. DMP‐based transistors prepared on rubbed n‐nonyltrichlorosilane‐modified SiO2/Si substrate gave the highest field‐effect mobility of 0.46 cm2/Vs, whereas DMT‐based transistor gave a mobility of 0.028 cm2/Vs. 相似文献
82.
Experiments of helical excitation using piezoelectric actuators on jet flows and lifted flames are performed to enhance the
understanding of the effects of vortical structures of various instability modes on the stabilization mechanism of the lifted
flame. In addition to the common ring and braid structures, five or seven azimuthal fingers (or lobes) can be identified in
the transverse image of the jet near field. Excitation with various helical modes enhances the azimuthal structures and entrainment
in the near field. When helically excited with the asymmetric m=1 mode, one of the fingers is enhanced and may evolve into a strong streamwise vortex. The streamwise vortices generated
in the braid region between the adjacent ring vortices may enhance fuel-air mixing due to additional azimuthal entrainment
upstream of a lifted flame when helically excited with the m=1 mode. Therefore, the streamwise vortex serves as an additional path of high probability of premixed flammable layer for
the upstream propagation of the lifted flame so that the flame base on one side of the lifted flame may extend farther upstream
and the flame base is inclined. In addition to the inclined flame base, multiple-legs phenomenon is also observed in the flame
base, which is strongly associated with fingers of the helical modes of the jet flow.
Received: 21 August 1997/Accepted: 24 January 1999 相似文献
83.
Jyh-Horng Sheu Kuie-Chi Chang Ping-Jyun Sung Chang-Yih Duh Ya-Ching Shen 《中国化学会会志》1999,46(2):253-257
A new marine sterol 7β-hydroperoxy-24-methylenecholesterol ( 1 ) along with five known compounds sarcophytol A ( 2 ), (Z)-N-[2-(4-hydroxyphenyl)ethyl]-3-methyldodec-2-enamide ( 3 ), 5α,7αH-eduesm-11(13)en-4α-ol ( 4 ), 24-methylenecholesterol ( 5 ) and 1β-hydroxy-α-cyperone ( 6 ) have been isolated from a Formosan soft coral Sinularia sp. The structures of the above compounds were determined by spectral analyses. Cytotoxicity of compounds 1–6 toward various cancer cell lines also is reported. 相似文献
84.
Wan-Chi Tsai Wen-Hung Wang Bo-Cian Huang Chiung-Yao Huang Jyh-Horng Sheu 《Molecules (Basel, Switzerland)》2021,26(22)
Pancreatic ductal adenocarcinoma is one of the most lethal malignancies: more than half of patients are diagnosed with a metastatic disease, which is associated with a five-year survival rate of only 3%. 5-epi-Sinuleptolide, a norditerpene isolated from Sinularia sp., has been demonstrated to possess cytotoxic activity against cancer cells. However, the cytotoxicity against pancreatic cancer cells and the related mechanisms are unknown. The aim of this study was to evaluate the anti-pancreatic cancer potential of 5-epi-sinuleptolide and to elucidate the underlying mechanisms. The inhibitory effects of 5-epi-sinuleptolide treatment on the proliferation of pancreatic cancer cells were determined and the results showed that 5-epi-sinuleptolide treatment inhibited cell proliferation, induced apoptosis and G2/M cell cycle arrest, and suppressed the invasion of pancreatic cancer cells. The results of western blotting further revealed that 5-epi-sinuleptolide could inhibit JAK2/STAT3, AKT, and ERK phosphorylation, which may account for the diverse cytotoxic effects of 5-epi-sinuleptolide. Taken together, our present investigation unveils a new therapeutic and anti-metastatic potential of 5-epi-sinuleptolide for pancreatic cancer treatment. 相似文献
85.
86.
The present study aims to accelerate the convergence to incompressible Navier–Stokes solution. For the sake of computational efficiency, Newton linearization of equations is invoked on non‐staggered grids to shorten the sequence to the final solution of the non‐linear differential system of equations. For the sake of accuracy, the resulting convection–diffusion–reaction finite‐difference equation is solved line‐by‐line using the proposed nodally exact one‐dimensional scheme. The matrix size is reduced and, at the same time, the CPU time is considerably saved due to the decrease of stencil points. The effectiveness of the implemented Newton linearization is demonstrated through computational exercises. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
87.
88.
F. R. Sheu R. T. Chern V. T. Stannett H. B. Hopfenberg 《Journal of Polymer Science.Polymer Physics》1988,26(4):883-892
Solubilities and diffusivities of CO2 and CH4 in two aromatic polyesters [Ardel® poly(bisphenol A phthalate) (PAr) and poly(phenolphthalein phthalate) (PPha)] and one polycarbonate [Lexan® (PC)], generated from independent sorption and permeation measurements at 35°C and up to 25 atm, are compared. The permeability ratio for CO2 over CH4, at 20 atm and 35°C, ranges from 24 for PC, to 21 for PAr, and 27 for PPha. However, the permeability of PPha and PAr are 40 and 120% higher, respectively, than that of PC. Less than 21% change in the gas diffusivity was observed; therefore, a major portion of the observed higher permeability of PPha and PAr is attributed to an increase in the gas solubility. These data are interpreted qualitatively in terms of changes in the calculated packing density, chain torsional mobility of the polymer, and gas-polymer attraction. 相似文献
89.
In this paper, we study the search directions of three important interior-point algorithms, namely, the primal-affine scaling method (with logarithmic barrier function), the dual-affine scaling method (with logarithmic barrier function), and the primal-dual interior point method. From an algebraic point of view, we show that the search directions of these three algorithms are merely Newton directions along three different paths that lead to a solution of the Karush-Kuhn-Tucker conditions of a given linear programming problem. From a geometric point of view, we show that these directions can be obtained by solving certain well-defined subproblems. Both views provide a general platform for studying the existing interior-point methods and deriving new interior-point algorithms. We illustrate the derivation of new interior-point algorithms by replacing the logarithmic barrier function with an entropic barrier function. The results have been generalized and discussed.This work is partially supported by the North Carolina Supercomputing Center 1990 Cray Grant Program sponsored by Cray Research. 相似文献
90.
Control of Luminescence by Tuning of Crystal Symmetry and Local Structure in Mn4+‐Activated Narrow Band Fluoride Phosphors 下载免费PDF全文
Mu‐Huai Fang Wei‐Lun Wu Prof. Dr. Ye Jin Tadeusz Lesniewski Dr. Sebastian Mahlik Prof. Dr. Marek Grinberg Prof. Dr. Mikhail G. Brik Dr. Alok M. Srivastava Dr. Chang‐Yang Chiang Prof. Dr. Wuzong Zhou Dr. Donghyuk Jeong Prof. Dr. Sun Hee Kim Dr. Grzegorz Leniec Prof. Dr. Slawomir M. Kaczmarek Dr. Hwo‐Shuenn Sheu Prof. Dr. Ru‐Shi Liu 《Angewandte Chemie (International ed. in English)》2018,57(7):1797-1801
Mn4+‐doped fluoride phosphors have been widely used in wide‐gamut backlighting devices because of their extremely narrow emission band. Solid solutions of Na2(SixGe1?x)F6:Mn4+ and Na2(GeyTi1?y)F6:Mn4+ were successfully synthesized to elucidate the behavior of the zero‐phonon line (ZPL) in different structures. The ratio between ZPL and the highest emission intensity υ6 phonon sideband exhibits a strong relationship with luminescent decay rate. First‐principles calculations are conducted to model the variation in the structural and electronic properties of the prepared solid solutions as a function of the composition. To compensate for the limitations of the Rietveld refinement, electron paramagnetic resonance and high‐resolution steady‐state emission spectra are used to confirm the diverse local environment for Mn4+ in the structure. Finally, the spectral luminous efficacy of radiation (LER) is used to reveal the important role of ZPL in practical applications. 相似文献