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61.
Hugues Verdure 《Archiv der Mathematik》2006,86(2):121-128
We give a simple criterion for the cyclicity of the m-torsion subgroup of the group of rational points on an elliptic curve defined over a finite field of characteristic larger
than 3 for m = 2, 3, 4, 6, 12.
Received: 25 January 2005 相似文献
62.
63.
We examine the 2++ gluonium spectrum in the framework of the Gauss-Weierstrass and Finite Energy QCD sum rules. The results of our analysis support the interpretation of the θ(1710) as a tensor glueball, but they also suggest the existence of at least another state with a massM?2 GeV and a width of about 200 MeV. 相似文献
64.
S. Lupia A. Giovannini R. Ugoccioni 《Zeitschrift fur Physik C Particles and Fields》1995,66(1-2):195-201
Clan structure analysis in rapidity intervals is generalized from negative binomial multiplicity distribution to the wide class of compound Poisson distributions. The link of generalized clan structure analysis with correlation functions is also established. These theoretical results are then applied to minimum bias events and evidentiate new interesting features, which can be inspiring and useful in order to discuss data on rapidity gap probability atTevatron andHera. 相似文献
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67.
Groves P Offermann S Rasmussen MO Canada FJ Bono JJ Driguez H Imberty A Jimenez-Barbero J 《Organic & biomolecular chemistry》2005,3(8):1381-1386
Lipochitooligosaccharides (LCOs) signal the symbiosis of rhizobia with legumes and the formation of nitrogen-fixing root nodules. LCOs 1 and 2 share identical tetrasaccharide scaffolds but different lipid moieties (1, LCO-IV(C16:1[9Z], SNa) and , LCO-IV(C16:2[2E,9Z], SNa)). The conformational behaviors of both LCOs were studied by molecular modeling and NMR. Modeling predicts that a small lipid modification would result in a different relative orientation of the lipid and tetrasaccharide moieties. Diffusion ordered spectroscopy reports that both LCOs form small aggregates above 1 mM. Nuclear Overhauser spectroscopy (NOESY) data, collected under monomeric conditions, reveals lipid-carbohydrate contacts only for 1, in agreement with the modeling data. The distinct molecular structures of 1 and 2 have the potential to contribute to their selective binding by legume proteins. 相似文献
68.
Lubineau A Lortat-Jacob H Gavard O Sarrazin S Bonnaffé D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(17):4265-4282
We have recently described the preparation of three building blocks for the combinatorial synthesis of heparan sulfate (HS) fragments. Herein we show that one of these building blocks (disaccharide 4) allows the preparation, in high yields and with total alpha stereoselectivity, of tetra-, hexa- and octasaccharides from the heparin (HP) regular region, by using 2+2, 2+4 and 4+4 glycosylation strategies, respectively. These oligosaccharides were processed into sulfated derivatives bearing an allyl moiety in the anomeric position. The UV-promoted conjugation of these compounds with alpha,omega-bis(thio)poly(ethylene glycol) spacers of three different lengths allowed us to prepare nine benzylated glycoconjugates. After final deprotection, the glycoconjugates 1 a-c, 2 a-c and 3 a-c were obtained and their ability to inhibit the interaction between IFN-gamma and HP was tested by using surface plasmon resonance detection. Compound 3 b, containing two HP octasaccharides linked by a 50-A linker was able to inhibit the IFN-gamma/HP interaction with an IC(50) value of approximately 35 nM. In addition, the nine glycoconjugates were perfect tools in the study to ascertain the topology of the IFN-gamma binding site on HS. Compounds 1 a-c, 2 a-c and 3 a-c, by mimicking the alternating sulfated and nonsulfated regions found in HS, thus comprise the first example of a library of synthetic HS mimetics giving access to the "second level of molecular diversity" found in HS. 相似文献
69.
Stefania Costa Pier Paolo Giovannini Giancarlo Fantin Alessandro Medici Paola Pedrini 《Helvetica chimica acta》2013,96(11):2124-2133
The biotransformations of cholic, deoxycholic, and hyocholic acids with Rhodococcus ruber are reported. In all biotransformations, the C17‐side chain is partially degraded, and the new 9,10‐secosteroids 4a (54%) and 4b (55%) are obtained from cholic and deoxycholic acids, respectively. The loss of H2O from C(11)? C(12) of secosteroids 4a and 4b affords the compounds 5a (5%) and 5b (20%), respectively. On the other hand, in the biotransformation of hyocholic acid with R. ruber the 9,10‐secosteroid 4c is not detected, but, rearranging to an intramolecular hemiacetal form, it evolves to the final furan derivative 6c (35%) by easy elimination of two molecules of H2O. The new secosteroids were characterized by IR, NMR, and 2D‐NMR spectroscopy, and mass spectroscopy. 相似文献
70.
Beatrice Nicolaï P. Espeau R. Céolin M. -A. Perrin L. Zaske J. Giovannini F. Leveiller 《Journal of Thermal Analysis and Calorimetry》2007,90(2):337-339
Spironolactone (C24H32O4S) usually crystallizes into an orthorhombic phase, named Form II. Another orthorhombic phase, named Form I, is also known
but seems difficult to obtain. Studies of the kinetics of desolvation of the ethanol solvate at room temperature showed that
these two forms can be obtained through different mechanisms of desolvation. 相似文献