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21.
Ivanov A. V. Gerasimenko A. V. Egorova I. V. Zaeva A. S. Novikova E. V. Rodionova N. A. Gowda V. Antzutkin O. N. 《Russian Journal of Coordination Chemistry》2018,44(8):518-531
Russian Journal of Coordination Chemistry - Chemisorption synthesis on the basis of the binuclear compound [Bi2{S2CN(C3H7)2}6] (I) and preparative isolation of the ion-polymeric heteronuclear... 相似文献
22.
Dihalobridged binuclear complexes [Rh(diolefin)(μ-X)]2 {diolefin = 1,5-cyclooctadiene (cod), X = Cl or Br; diolefin = norbornadiene (nbd), X = Cl}, undergo halide bridge cleavage reactions with multidentate N,N-heterocycles 1,3,5-tris(benzimidazolyl)benzene (L1H3), 1,3,5-tris(N-methylbenzimidazolyl)benzene (L2H3) and N,S-heterocycle 1,3,5-tris(benzothiazolyl)benzene (L3H3) to yield trinuclear heterocycle bridged complexes [{RhX(cod)}3(μ-LH3)] and [{RhCl(nbd)}3(μ-LH3)] (LH3 = L1H3, L2H3, L3H3). 1H NMR exchange measurements have shown resonances for olefinic protons 1″, 2″, 5″ and 6″ of cod at different chemical shifts, perhaps due to restricted Rh–N bond rotation. The olefinic and aliphatic protons would undergo exchange with each other and also with intermediate species. The exchange mechanism may be visualized to involve Rh–N bond breaking, rotation of the cod ligand of the T-shaped (three-coordinate) intermediate species followed by recomplexation. An alternate mechanism may be Rh–cod bond breaking at olefin positions 5″ and 6″, isomerisation of the T-complex such that 5″/6″ moves trans to X coupled with rotation of the heterocycle about the Rh–N bond (made easier by the reduced coordination number of the intermediate), followed by recoordination of 1″/2″ trans to N, followed by recomplexation. NMR signals from the intermediate species in one dimensional 1H, 13C and 2D NMR spectra have supported the exchange of protons. 相似文献
23.
B. N. Lakshminarayana C. R. Gnanendra T. N. Mahadeva Prasad M. A. Sridhar Nagaraja Naik D. Chenne Gowda J. Shashidhara Prasad 《Journal of chemical crystallography》2010,40(8):686-690
Abstract
The novel 3-methyl-2,6-dip-toylpiperidine-4-one was acylated by 3-chloropropanoychloride and subjected for dehydrohalogenation. The synthesized compound was characterized by spectroscopic techniques and finally confirmed by X-ray diffraction studies. The molecule crystallizes in the monoclinic crystal class in the space group C 2/c with cell parameters a = 18.538(2) ?, b = 9.9050(1) ?, c = 22.954(2) ?, β = 94.486(8)° and Z = 8. The piperidine ring adopts a twist boat conformation. 相似文献24.
Given a continuous P0-function F : Rn Rn, we describe a method of constructing trajectories associated with the P0-equation F(x) = 0. Various well known equation-based reformulations of the nonlinear complementarity problem and the box variational inequality problem corresponding to a continuous P0-function lead to P0-equations. In particular, reformulations via (a) the Fischer function for the NCP, (b) the min function for the NCP, (c) the fixed point map for a BVI, and (d) the normal map for a BVI give raise to P0-equations when the underlying function is P0. To generate the trajectories, we perturb the given P0-function F to a P-function F(x, ); unique solutions of F(x, ) = 0 as varies over an interval in (0, ) then define the trajectory. We prove general results on the existence and limiting behavior of such trajectories. As special cases we study the interior point trajectory, trajectories based on the fixed point map of a BVI, trajectories based on the normal map of a BVI, and a trajectory based on the aggregate function of a vertical nonlinear complementarity problem. 相似文献
25.
The kinetics of oxidation of arginine, histidine, and threonine by chloramine-T (CAT) have been investigated in alkaline medium at 35°C. The rates are first order in both [CAT] and [amino acid] and inverse fractional order in [OH?] for arginine and histidine. The rate is independent of [OH?] for threonine. Variation of ionic strength and addition of the reaction product, p-toluenesulfonamide, or Cl? ions had no effect on the rate. A decrease of the dielectric constant of the medium by adding methanol decreased the rate with arginine, while the rates increased with histidine and threonine. The solvent isotope effect was studied using D2O. (kobs)/(kobs) was found to be 0.55 and 0.79 for arginine and histidine, respectively. The reactions were studied at different temperatures, and activation parameters have been computed. The oxidation process in alkaline medium, under conditions employed in the present investigations, has been shown to proceed via two paths, one involving the interaction of RNHCl (formed rapidly from RNCl?), with the amino acid in a slow step to form monochloroamino acid, which subsequently interacts with another molecule of RNHCl in a fast step to give the products, p-toluenesulfonamide (RNH2), and the corresponding nitrile of the amino acid (R'CN). The other path involves the interaction of RNCl? with the amino acid in a similar way to give RNH2 and R'CN. Mechanisms proposed and the derived rate laws are consistent with the observed kinetics. The rate constants predicted using the derived rate laws, as [OH?] varies, are in excellent agreement with the observed rate constants, thus justifying these rate laws and hence the proposed mechanistic schemes. 相似文献
26.
27.
.?AdimurthiEmail author G.?D.?Veerappa?Gowda 《NoDEA : Nonlinear Differential Equations and Applications》2004,11(3):335-348
We give an explicit formula for a solution of Hamilton-Jacobi equation ut+H(u,Du)=0 in
with initial condition u(x,0)=u0(x), where p H(u,p) is convex, positively homogeneous of degree one and the Hamiltonian H need not satisfy the monotonicity condition in u. 相似文献
28.
Mahesh M. SavantNeetha S. Gowda Akshay M. PansuriyaChirag V. Bhuva Naval KapuriyaSridhar M. Anandalwar Shashidhara J. PrasadAnamik Shah Yogesh T. Naliapara 《Tetrahedron letters》2011,52(2):254-257
A highly efficient strategy to 2,3-substituted chromen-4H-ones has been developed. The methodology involves unexpected intramolecular heteroannulation of readily accessible substituted 2-hydroxy-ω-nitroacetophenone with carbon disulfide in the presence K2CO3 followed by methylation with methyl iodide. These chromenones were further reacted with various nucleophiles such as amines, thiols, and alkoxide resulting in the facile C-N, C-S, and C-O bond formation. The scope and generality have been discussed. 相似文献
29.
30.
We correct an error in the statement of Theorem 8 in [1].
Received: January 3, 2001 / Accepted: February 26, 2001?Published online May 18, 2001 相似文献