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961.
Quasistatic Crack Growth in Nonlinear Elasticity 总被引:2,自引:0,他引:2
Gianni Dal?MasoEmail author Gilles A.?Francfort Rodica?Toader 《Archive for Rational Mechanics and Analysis》2005,176(2):165-225
In this paper, we prove a new existence result for a variational model of crack growth in brittle materials proposed in [19]. We consider the case of n-dimensional nonlinear elasticity, for an arbitrary n1, with a quasiconvex bulk energy and with prescribed boundary deformations and applied loads, both depending on time. 相似文献
962.
Kaushik Bhattacharya Irene Fonseca Gilles Francfort 《Archive for Rational Mechanics and Analysis》2002,161(3):205-229
We examine the asymptotic behavior of a bilayer thin film using the notion of Γ-convergence. We allow for debonding at the interface, but penalize it using an interfacial energy; thus the functional we consider consists of the elastic energy of the two layers and the interfacial energy with penalized debonding. We show that the asymptotic theory or Γ-limit depends on the particular form of the interfacial energy, and derive detailed results for both the cohesive and the brittle interface. 相似文献
963.
Sans résumé
Memoire presenté par J. L. Lions 相似文献
964.
Dr. Maria Gil-Moles Sebastian Türck Dr. Uttara Basu Dr. Andrea Pettenuzzo Dr. Saurav Bhattacharya Ananthu Rajan Xiang Ma Rolf Büssing Jessica Wölker Dr. Hilke Burmeister Henrik Hoffmeister Pia Schneeberg Andre Prause Petra Lippmann Josephine Kusi-Nimarko Dr. Storm Hassell-Hart Dr. Andrew McGown Dr. Daniel Guest Dr. Yan Lin Dr. Anna Notaro Dr. Robin Vinck Dr. Johannes Karges Dr. Kevin Cariou Dr. Kun Peng Dr. Xue Qin Dr. Xing Wang Dr. Joanna Skiba Dr. Łukasz Szczupak Prof. Dr. Konrad Kowalski Prof. Dr. Ulrich Schatzschneider Dr. Catherine Hemmert Prof. Dr. Heinz Gornitzka Prof. Dr. Elena R. Milaeva Dr. Alexey A. Nazarov Prof. Dr. Gilles Gasser Prof. Dr. John Spencer Dr. Luca Ronconi Prof. Dr. Ulrich Kortz Prof. Dr. Jindrich Cinatl Prof. Dr. Denisa Bojkova Prof. Dr. Ingo Ott 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(71):17928-17940
The global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has called for an urgent need for dedicated antiviral therapeutics. Metal complexes are commonly underrepresented in compound libraries that are used for screening in drug discovery campaigns, however, there is growing evidence for their role in medicinal chemistry. Based on previous results, we have selected more than 100 structurally diverse metal complexes for profiling as inhibitors of two relevant SARS-CoV-2 replication mechanisms, namely the interaction of the spike (S) protein with the ACE2 receptor and the papain-like protease PLpro. In addition to many well-established types of mononuclear experimental metallodrugs, the pool of compounds tested was extended to approved metal-based therapeutics such as silver sulfadiazine and thiomersal, as well as polyoxometalates (POMs). Among the mononuclear metal complexes, only a small number of active inhibitors of the S/ACE2 interaction was identified, with titanocene dichloride as the only strong inhibitor. However, among the gold and silver containing complexes many turned out to be very potent inhibitors of PLpro activity. Highly promising activity against both targets was noted for many POMs. Selected complexes were evaluated in antiviral SARS-CoV-2 assays confirming activity for gold complexes with N-heterocyclic carbene (NHC) or dithiocarbamato ligands, a silver NHC complex, titanocene dichloride as well as a POM compound. These studies might provide starting points for the design of metal-based SARS-CoV-2 antiviral agents. 相似文献
965.
In this work, the tuneability of the π acceptor or donor properties of a set of N‐heterocyclic carbenes (NHCs) with a wide spectrum of electronic characteristics is established by means of density functional theory and energy decomposition analysis (EDA) tools. Even though the main orbital interaction contribution to the NHC coordination is the σ donation, a significant contribution of the π interactions to the bond is observed. By means of carefully selected coordination sites, different contributions to the π interactions could be identified and isolated. It includes not only the well known back donation and donation interactions, but also the intrafragment polarization, which has not been considered in previous studies. This can be obtained through the use of the extended transition state method for EDA combined with the natural orbitals for chemical valence and the constrained space orbital variation analysis. The contributions vary with the position of the heteroatoms and the presence of exocyclic substituents; the donation/backdonation π interactions between NHC and the coordination site can range between 2 and 61% of the total π orbital interactions, while the rest is owed to intrafragment polarization. Our results do not only contribute to the understanding of the electronic structure of NHC‐based complexes, giving ways to improve their catalytic properties, but also provide comprehension on the modelization methods used to study their donor–acceptor interactions. © 2015 Wiley Periodicals, Inc. 相似文献
966.
967.
Oleksiy V. Khavryuchenko Lidong Wang Dariusz Mitoraj Gilles H. Peslherbe 《Journal of Coordination Chemistry》2015,68(17-18):3317-3327
Coordinative incorporation of Co(II/III) cocatalytic sites into organic–inorganic hybrids of TiO2 and “polyheptazine” (PH, poly(aminoimino)heptazine, melon, or “graphitic carbon nitride”) has been investigated both by quantum chemical calculations and experimental techniques. Specifically, density-functional theory (DFT) calculations (PBE/def2-TZVPP) suggest that Co(II/III) and Zn(II) ions adsorb in nanocavities at the surface of the hybrid PH–TiO2 cluster, a prediction which can be further confirmed experimentally by 15N nuclear magnetic resonance in the case of the Zn complex. The absorption spectra of the complexes were characterized by time-dependent DFT calculations, suggesting a change of color upon Co ion binding which can in fact be observed with the naked eye. Hybrid TiO2–PH photoelectrodes were impregnated with Co(II) ions from aqueous cobalt nitrate solutions. Optical absorption data suggest that Co(II) ions are predominantly present as single ions coordinated within the nitrogen cavities of TiO2–PH, and any undesired blocking of light absorption is negligible. The cobalt-induced cocatalytic sites can efficiently couple to the holes photogenerated by visible light in TiO2–PH, leading to complete oxidation of water to dioxygen. Our results indicate that coordinative incorporation of metal ions into well-designed surface sites in the light absorber is sufficient to drive complex multielectron transformations in artificial photosynthetic systems. 相似文献
968.
Sabrina Belaid Ouassini Benali-Baïtich Gilles Bouet Anne Landreau 《Chemical Papers》2015,69(10):1350-1360
New oxovanadium(IV) and cadmium(II) complexes with reduced Schiff bases derived from N,N′-o-phenylenebis(salicylideneimine) have been synthesized and characterized using infrared and UV-visible spectra, ESR, and thermogravimetry. The complexes were identified as [ML] · (H2O) species, where deprotonated ligands are coordinated to metal through N2O2 donor atoms. Antioxidant activity of the ligands and complexes was evaluated, revealing that the complexes exhibit a higher scavenging activity than the corresponding ligands. The prepared cadmium complexes showed slightly higher activity than the vanadium ones. Antifungal activity was tested against different human fungi including yeasts of the Candida genus (C. albicans and C. glabrata) and an opportunistic mould Aspergillus fumigatus. The oxovanadium complexes exhibited a very low activity toward C. albicans while the cadmium ones showed a significant growth inhibition of all the fungi tested; mainly of A. fumigatus though this mould is poorly susceptible to current antifungal agents like Itraconazole. 相似文献
969.
Souad Bennabi Nabahat Sahli Mohammed Belbachir Claire-Helene Brachais Gilles Boni Jean-Pierre Couvercelle 《高分子科学杂志,A辑:纯化学与应用化学》2017,54(11):843-852
In this works, we have explored a new method for a green synthesis of poly(ethylglyoxylate) (PEtG). This method consists on using a montmorillonite clay called “Maghnite-H+” as an eco-catalyst to replace triethylamine which is toxic. Cationic polymerization experiments are performed in bulk conditions at three temperatures (?40°C, 25°C, 80°C) and in THF solutions at room temperature (25°C). At 25°C, an optimum ratio of 5 wt% of catalyst leads to molar masses up to 22000 g/mol in THF solutions. Polymerizations in bulk conditions lead to slightly lower masses than experiments conducted in THF solutions. However, bulk polymerization of ethyleglyoxylate remains a preferable method in order to avoid the use of a solvent and therefore to stay in the context of green chemistry. The structure of obtained polymers are characterized and confirmed by 1H and 13C NMR. Thermogravimetric Analysis (TGA) shows an enhanced thermal stability for end-capped PEtG compared to non-terminated PEtG. The best conversion rate (92%) is observed in bulk conditions at 25°C for a reaction time of 48h. An activation energy could be calculated from bulk experiments (Ea = 6.9 kJ/mol). An interesting advantage of Maghnite-H+ is an easy recoverage by a simple filtration from the polymer solution. 相似文献
970.