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991.
Liladhar Waykole Mahavir Prashad Stephen Palermo Oljan Repic Thomas J. Blacklock 《合成通讯》2013,43(12):2159-2163
A practical synthesis of 2-(bromomethyl)naphthalene (1), by selective benzylic bromination of 2-methylnaphthalene (2), with bromine in heptane in the presence of lanthanum acetate hydrate is described. 相似文献
992.
A convenient three‐step route toward a functionalized pyrrole building block for novel anti‐inflammatory agents is reported. In contrast to previous strategies, the present approach focuses on inexpensive starting materials and application on a multigram scale. A high degree of functional diversity is demonstrated in various derivatives, and the scope and limitations of this route are discussed. Complementary to the described tetrasubstituted pyrroles, a novel ring‐closure protocol based on the Feist–Benary condensation affords trisubstituted analogues. 相似文献
993.
Thomas Behrsing Glen B. Deacon Peter C. Junk Brian W. Skelton Alexandre N. Sobolev Allan H. White 《无机化学与普通化学杂志》2013,639(1):41-48
Reaction of LnCl3 with Na2(PDDA) (PDDA = phenylene‐1, 2‐dioxydiacetate) in a 1 to 2 mol ratio in aqueous solution yielded [Ln2(PDDA)3(H2O)6] · 2H2O, structurally characterized for Ln = Ce ( 1 ), Sm ( 2 ) (redetermination), Tb ( 3 ) and Y ( 4 ) in a monoclinic C2/c array, a second related structural form [orthorhombic, Pbcn] being obtained for Tb ( 5 ), Ho ( 6 ) and Er ( 7 ). The ‘domains of existence' of these two previously described forms are now extended to Ce–Dy, Y, and Eu–Er, respectively. Reaction under the same conditions for the heavier Yb3+ ion yielded [Yb2(PDDA)3(H2O)6](∞|∞) · 4H2O ( 8 ), orthorhombic, Pbca. In the case of Ln = La the bimetallic species [NaLa(PDDA)2(H2O)2](∞|∞) · 4H2O ( 9 ) was obtained, while reaction of LnCl3 with Na2(PDDA) in a 1 to 3 mol ratio led to the isolation of the isotypic (monoclinic, P21/c) [NaLn(PDDA)2(H2O)2](∞|∞) · 4H2O) for Ln = Ce ( 10 ) and Sm ( 12 ). With the smaller Ln = Yb, the more definitively bimetallic [NaYb(PDDA)2(H2O)2](∞|∞) · 3H2O ( 13 ) (triclinic, P$\bar{1}$ )) was obtained, the trihydrate solvation ascribed differing from that recorded (dihydrate) in a cosynchronous report. 相似文献
994.
A one-step synthesis of the stable [4]helicenium dye, 1,13-dimethoxy-chromeno[2,3,4-kl]xanthenium hexafluorophosphate (DMCX+) from the readily available tris(2,6-dimethoxyphenyl)carbenium ion is reported. The crystal structure, the chemical stability, and dye properties of the DMCX+ helicenium system are described. 相似文献
995.
996.
997.
Hiroshi Watanabe Marcus Elstner Thomas Steinbrecher 《Journal of computational chemistry》2013,34(3):198-205
Molecular mechanics methods have matured into powerful methods to understand the dynamics and flexibility of macromolecules and especially proteins. As multinanosecond to microsecond length molecular dynamics (MD) simulations become commonplace, advanced analysis tools are required to generate scientifically useful information from large amounts of data. Some of the key degrees of freedom to understand protein flexibility and dynamics are the amino acid residue side chain dihedral angles. In this work, we present an easily automated way to summarize and understand the relevant dihedral populations. A tremendous reduction in complexity is achieved by describing dihedral timeseries in terms of histograms decomposed into Gaussians. Using the familiar and widely studied protein lysozyme, it is demonstrated that our approach captures essential properties of protein structure and dynamics. A simple classification scheme is proposed that indicates the rotational state population for each dihedral angle of interest and allows a decision if a given side chain or peptide backbone fragment remains rigid during the course of an MD simulation, adopts a converged distribution between conformational substates or has not reached convergence yet. © 2012 Wiley Periodicals, Inc. 相似文献
998.
Thomas A. Manz 《Journal of computational chemistry》2013,34(5):418-421
In recent years, several methods have been developed that partition the electron density among atoms using spherically symmetric atomic weights. D. E. P. Vanpoucke, P. Bultinck, and I. Van Driessche (J. Comput. Chem. 2012, doi: 10.1002/jcc.23088) recently reported a periodic implementation of the Hirshfeld‐I method that uses a combination of Becke‐style and uniform integration grids and modified atomic reference densities to compute net atomic charges in periodic materials. Herein, this method is discussed in the context of earlier periodic implementations of the Hirshfeld‐I method, the Iterated Stockholder Atoms method, and the density derived electrostatic and chemical method. 相似文献
999.
Adnan Aydemir Necmettin Yildirim Bernd Hitzmann Thomas Scheper 《Journal of mathematical chemistry》2013,51(6):1532-1547
A mathematical model is presented for the kinetic resolution of racemates. It takes all intermediate binding steps into account and assumes that such steps are reversible. The model describing dynamics of the chiral reaction products consists of two nonlinear differential equations. With this model, the enantioselectivity of enzyme has been studied. Mathematical and numerical simulation of the model show that there are several ways to control the enantiomeric ratio (E) but the affinity and the binding rates of the intermediate enzyme complex to the racemic substrates are the key steps for the enzyme enantioselectivity. 相似文献
1000.
A Commentary on the paper ”Studies on liquid‐crystalline glycosides" by Volkmar Vill, Thomas Böcker, Joachim Thiem and Fred Fischer. First published in Liquid Crystals, 6, 349‐356 (1989). 相似文献