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101.
102.
The torsional frequencies have been rigorously evalulated in the compounds 1,2,4,5-tetrachloro-3,6-dinitrobenzene and 1,3,5-trichloro-2,4-dinitrobenzene
over an extended temperature range (77K–392K) using the experimental results of NQR and crystal structure data. The values
have been compared with those obtained by using the X-ray thermal parameters. 相似文献
103.
Sastry A. Kunda Terri L. Smith Mark D. Hylarides G.W. Kabalka 《Tetrahedron letters》1985,26(3):279-280
The chlorination of (E)-vinylboronic acids produces (z)-vinyl chlorides. 相似文献
104.
T.C. DinadayalaneG.Narahari Sastry 《Tetrahedron》2003,59(42):8347-8351
Computations on a series of sumanene and pinakene isomers reveal that the isolated pentagon species are found to be more stable than non-isolated pentagon structures. However, the present study indicates that there is no correlation between the bowl-to-bowl inversion barrier and the relative stability. Unexpectedly, the least stable isomer has the lowest bowl-to-bowl inversion barrier in pinakene isomers. Thus, curvature cannot be taken as a measure to evaluate the stability of buckybowls. The relative energy ordering and HOMO-LUMO gap correlate well in the series of pinakene isomers considered. 相似文献
105.
Summary Simple and sensitive spectrophotometric methods for the determination of proline, hydroxyproline, aspartic acid, arginine and histidine, based on the formation of a coloured species with metol and sodium hypochlorite or chloramine-T are described. The effect of other amino acids and the best conditions for forming coloured complexes have been studied. The methods are applicable to the determination of the aforementioned amino acids in pure samples and in protein hydrolysates.
Spektrophotometrische Bestimmung von Aminosäuren mit Metol und Natriumhypochlorit oder Chloramin T
Zusammenfassung Einfache und empfindliche Spektrophotometrische Methoden zur Bestimmung von Prolin, Hydroxyprolin, Asparaginsäure, Arginin und Histidin mit Hilfe der Farbreaktion mit Metol und Natriumhypochlorit oder Chloramin T wurden beschrieben. Die Einwirkung anderer Aminosäuren sowie die besten Bedingungen für die Farbreaktion wurden untersucht. Die erwähnten Verfahren eignen sich sowohl für die Bestimmung der erwähnten Aminosäuren in reinem Zustand wie auch in Proteinhydrolysaten.相似文献
106.
The push for better understanding and design of complex systems requires the solution of challenging optimization problems with large numbers of decision variables. This note presents principled results demonstrating the scalable solution of a difficult test function on instances over a billion variables using a parallel implementation of a genetic algorithm (GA). The problem addressed is a noisy, blind problem over a vector of binary decision variables. Noise is added equaling a tenth of the deterministic objective function variance of the problem, thereby making it difficult for simple hillclimbers to find the optimal solution. The genetic algorithm used—the compact GA—is able to find the optimum in the presence of noise quickly, reliably, and accurately, and the solution scalability follows known convergence theories. These results on noisy problem together with other results on problems involving varying modularity, hierarchy, and overlap foreshadow routine solution of billion‐variable problems across the landscape of complexity science. © 2007 Wiley Periodicals, Inc. Complexity 12: 27–29, 2007 相似文献
107.
S. E. Noorjahan T. P. Sastry 《Journal of polymer science. Part A, Polymer chemistry》2004,42(9):2241-2252
Fibrin–gelatin composite (PFG) films were prepared and crosslinked with glutaraldehyde as reported by us previously. These composites were graft‐copolymerized with poly(2‐hydroxyethyl methacrylate) (PHEMA) and poly(2‐hydroxypropyl methacrylate) (PHPMA) with a potassium persulfate and sodium metabisulfite redox initiation system. The graft copolymers (PFG‐HEMA and PFG‐HPMA) were characterized for their percentage of grafting, percentage of equilibrium water content, and percentages of free water and bound water. The chemical composition and thermal, mechanical, morphological, and surface characteristics were also evaluated. The optimum conditions for obtaining a maximum percentage of grafting were standardized. PFG and its graft copolymers exhibited higher equilibrium water contents ranging from 60 to 77% when compared with those of HEMA and HPMA homopolymers. DSC studies revealed increased freezing water contents and decreased bound‐water contents for the graft copolymers when compared with those of PFG alone. These properties improved the efficacy of hydrogels. PFG demonstrated better mechanical properties as compared with its graft copolymers. This may be attributed to the alkaline reaction conditions wherein protein hydrolysis of PFG would have occurred thereby reducing the overall strength of the graft copolymers. IR and scanning electron microscopic studies confirmed the grafting of PHEMA and PHPMA onto PFG. Contact‐angle studies revealed increased polarity for graft copolymers, which is a symbol for increased hydrophilicity. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2241–2252, 2004 相似文献
108.
S. Kalavathi J. Janaki G. V. R. Reddy G. V. N. Rao V. Sankara Sastry Y. Hariharan 《Physica C: Superconductivity and its Applications》2003,390(4):296-304
The structural, electrical and magnetic properties of the superconducting ferromagnets, Gd1.4−xDyxCe0.6Sr2RuCu2O10 (x=0–0.6) are systematically investigated as a function of Dy doping and temperature. These compounds are characterized by high temperature superconductivity (Tc ranging from 20 to 40 K depending upon the Dy content) co-existing with weak ferromagnetism with two magnetic transitions (TM2 ranging from 95 to 106 K and TM1 around 120 K). Doping with Dy gives no significant structural changes except for a minor change in the c/a ratio. However the superconducting transition temperature is significantly suppressed and magnetic ordering temperature enhanced on Dy doping. These effects are described and discussed. 相似文献
109.
The method of optical model analysis of generalized elastic scattering angular distributions (GESA) has been applied to heavy
ion scattering to derive fusion spin distributions. This method is used to reproduce the coupled channel fusion spin distributions.
When applied to experimental data, particularly to the fissile systems like16O +232Th, the method gives large mean square spin values in agreement with “anomalous” values derived from experimental fission
fragment anisotropies. 相似文献
110.
It has been established that quasicrystals with icosahedral point group symmetry occur in a rapidly solidified Mg32 (Al, Zn)49 alloy chosen on the basis of its equilibrium crystal structure. This alloy has a natural tendency to form icosahedral atomic
clusters stabilised by size difference amongst constituent atoms. Results highlight the relationship between equilibrium crystal
structure and the tendency to form quasicrystals. 相似文献