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991.
992.
We consider the Neumann problem for the Hénon equation. We obtain existence results and we analyze the symmetry properties of the ground state solutions. We prove that some symmetry and variational properties can be expressed in terms of eigenvalues of a Steklov problem. Applications are also given to extremals of certain trace inequalities. 相似文献
993.
994.
Caterina Fraschetti Antonello Filippi Maria Elisa Crestoni Enrico Marcantoni Marco Glucini Laura Guarcini Maria Montagna Leonardo Guidoni Maurizio Speranza 《Journal of the American Society for Mass Spectrometry》2016,27(4):615-621
A potassium-containing hexaazamacrocyclic dication, [M?H?K]2+, is able to add in the gas phase mono- and dicarboxylate anions as well as inorganic anions by forming the corresponding monocharged adducts, the structure of which markedly depends on the basicity of the anion. With anions, such as acetate or fluoride, the neutral hexaazamacrocycle M acts as an acceptor of monosolvated K+ ion. With less basic anions, such as trifluoroacetate or chloride, the protonated hexaazamacrocycle [M?H]+ performs the unusual functions of an acceptor of contact K+/anion pairs. 相似文献
995.
Dr. Giuseppe Soavi Dr. Alessandro Pedrini Dr. Anjali Devi Das Prof. Francesca Terenziani Prof. Roberta Pinalli Dr. Neal Hickey Dr. Barbara Medagli Prof. Silvano Geremia Prof. Enrico Dalcanale 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(23):e202200185
Inclusion of polymethine cyanine dyes in the cavity of macrocyclic receptors is an effective strategy to alter their absorption and emission behavior in aqueous solution. In this paper, the effect of the host-guest interaction between cucurbit[8]uril (CB[8]) and a model trimethine indocyanine (Cy3) on dye spectral properties and aggregation in water is investigated. Solution studies, performed by a combination of spectroscopic and calorimetric techniques, indicate that the addition of CB[8] disrupts Cy3 aggregates, leading to the formation of a 1 : 1 host-guest complex with an association constant of 1.5×106 M−1. At concentrations suitable for NMR experiments, the slow formation of a supramolecular polymer was observed, followed by precipitation. Single crystals X-ray structure elucidation confirmed the formation of a polymer with 1 : 1 stoichiometry in the solid state. 相似文献
996.
Danilo Marchetti Francesca Portone Prof. Francesco Mezzadri Prof. Enrico Dalcanale Dr. Mauro Gemmi Dr. Alessandro Pedrini Prof. Chiara Massera 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(72):e202202977
The dynamic behavior of supramolecular organic frameworks (SOFs) based on the rigid tetra-4-(4-pyridyl)phenylmethane ( TPPM) organic tecton has been elucidated through 3D electron diffraction, X-ray powder diffraction and differential scanning calorimetry (DSC) analysis. The SOF undergoes a reversible single-crystal-to-single-crystal transformation when exposed to vapours of selected organic solvents, moving from a closed structure with isolated small voids to an expanded structure with solvated channels along the b axis. The observed selectivity is dictated by the fitting of the guest in the expanded SOF, following the degree of packing coefficient. The effect of solvent uptake on TPPM solid-state fluorescence was investigated, evidencing a significant variation in the emission profile only in the presence of chloroform. 相似文献
997.
Prof. Enrico Cavalli Dr. Chiara Nardon Oliver G. Willis Dr. Francesco Zinna Prof. Lorenzo Di Bari Silvia Mizzoni Dr. Silvia Ruggieri Salvatore C. Gaglio Dr. Massimiliano Perduca Prof. Claudio Zaccone Prof. Alessandro Romeo Prof. Fabio Piccinelli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(37):e202200574
We report the first example of very efficient NIR Circularly Polarized Luminescence (CPL) (around 970 nm) in water, obtained thanks to the combined use of a chiral Yb complex and of poly lactic-co-glycolic acid (PLGA) nanoparticles. [Yb L (tta)2]CH3COO ( L =N, N’-bis(2-pyridylmethylidene)-1,2-(R,R+S,S) cyclohexanediamine and tta=2-thenoyltrifluoroacetonate) shows good CPL in organic solvents, because the tta ligands efficiently sensitize Yb NIR luminescence and the readily prepared chiral ligand L endows the complex with the necessary dissymmetry. PLGA nanoparticles incorporate the complex and protect the metal ion from the intrusion of solvent molecules, while ensuring biocompatibility, water solubility and stability to the complex. Hydrophilic NIR-CPL optical probes can find applications in the field of NIR-CPL bio-assays. 相似文献
998.
Giuseppe Molteni Enrico Serra Massimo Tarallo Susanna Terracini 《Archive for Rational Mechanics and Analysis》2006,182(1):77-123
We study the existence of small amplitude oscillations near elliptic equilibria of autonomous systems, which mix different
normal modes. The reference problem is the Fermi-Pasta-Ulam β-model: a chain of nonlinear oscillators with nearest-neighborhood interaction. We develop a new bifurcation approach that
locates secondary bifurcations from the unimodal primary branches. Two sufficient conditions for bifurcation are given: one
involves only the arithmetic properties of the eigenvalues of the linearized system (asymptotic resonance), while the other takes into account the nonlinear character of the interaction between normal modes (nonlinear coupling). Both conditions are checked for the Fermi-Pasta-Ulam problem. 相似文献
999.
Dr. Kripasindhu Sardar Enrico Petrucco Craig I. Hiley Dr. Jonathan D. B. Sharman Dr. Peter P. Wells Prof. Andrea E. Russell Dr. Reza J. Kashtiban Dr. Jeremy Sloan Prof. Richard I. Walton 《Angewandte Chemie (International ed. in English)》2014,53(41):10960-10964
The pyrochlore solid solution (Na0.33Ce0.67)2(Ir1?xRux)2O7 (0≤x≤1), containing B‐site RuIV and IrIV is prepared by hydrothermal synthesis and used as a catalyst layer for electrochemical oxygen evolution from water at pH<7. The materials have atomically mixed Ru and Ir and their nanocrystalline form allows effective fabrication of electrode coatings with improved charge densities over a typical (Ru,Ir)O2 catalyst. An in situ study of the catalyst layers using XANES spectroscopy at the Ir LIII and Ru K edges shows that both Ru and Ir participate in redox chemistry at oxygen evolution conditions and that Ru is more active than Ir, being oxidized by almost one oxidation state at maximum applied potential, with no evidence for ruthenate or iridate in +6 or higher oxidation states. 相似文献
1000.