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991.
992.
Jinxuan Liu Wencai Zhou Jianxi Liu Ian Howard Goran Kilibarda Sabine Schlabach Damien Coupry Matthew Addicoat Satoru Yoneda Yusuke Tsutsui Tsuneaki Sakurai Shu Seki Zhengbang Wang Peter Lindemann Engelbert Redel Thomas Heine Christof Wll 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(25):7549-7553
993.
994.
Nicolas Coudurier Mikhail Chubarov Raphaël Boichot Frderic Mercier Elisabeth Blanquet Roman Reboud Sabine Lay Alexandre Crisci Stphane Coindeau Thierry Encinas Michel Pons 《Crystal Research and Technology》2016,51(3):231-238
Boron Nitride is a promising group 13–group 15 compound material that exhibits various interesting properties like wide band gap, chemical stability, attractive mechanical properties and other. The growth behavior of this material has not been investigated in sufficient details to tailor properties of the resulting films. In this work we present the results on the growth of turbostratic boron nitride (t‐BN) thin films at a relatively high growth rate of 3 μm/h with the aim to investigate the potential use of boron trichloride in combination with ammonia as precursors for growth. Deposition experiments were conducted in a vertical cold wall high temperature chemical vapor deposition reactor in the temperature range 1000°C–1700°C depending on the substrate used. Templates of w‐AlN (0001), 4° off‐cut 4H‐SiC (0001), Cr (110) and W (110) were employed as substrates for the BN growth. As‐grown BN layers were characterized by Scanning Electron Microscopy, X‐Ray Diffraction, Electron Diffraction and Raman Spectroscopy. The results indicate that temperature and N/B ratio have a great influence on the crystallinity of the deposited films. For AlN and SiC substrates, a temperature of 1600°C and N/B ratio in range between 3 and 7.5 were identified as the best parameters for the growth of a 2 μm thick t‐BN layer with a spacing between basal planes of about 3.36 Å compare to the 3.33 Å spacing between basal planes of hexagonal or rhombohedral BN (h‐BN or r‐BN). For Cr and W substrates which have a lower mismatch with h‐BN (1 and 8.8 %), layers of t‐BN were deposited at much lower temperature (1000°C–1150°C) with a spacing between basal planes of 3.5 Å and morphology similar to that observed on SiC substrates. We obtained t‐BN layers with in plane strong disorder but out of plane orientation (c‐axis normal to the surface). 相似文献
995.
Dipl.‐Chem. Markus Mansueto Dr. Wolfgang Frey Prof. Dr. Sabine Laschat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(47):16058-16065
Novel chiral amino acid derived ionic liquid crystals with amine and amide moieties as spacers between the imidazolium head group and the alkyl chain were synthesised. The key step in the synthesis utilised the relatively uncommon SO3 leaving group in a microwave‐assisted reaction. The mesomorphic properties of the mesogens were determined by differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X‐ray diffraction. All liquid crystalline salts exhibit a smectic A mesophase geometry with strongly interdigitated bilayer structures. An increase of the steric bulk of the stereogenic centre hindered the formation of mesophases. In case of phenylalanine‐derived derivatives a mesomorphic behaviour was observed for shorter alkyl chains as compared to other amino acid derivatives indicating an additional stabilising effect by the phenyl moiety. 相似文献
996.
Dr. Paloma Vidal Dr. Virginia Roldós Dr. María del Carmen Fernández‐Alonso Dr. Boris Vauzeilles Prof. Dr. Yves Bleriot Prof. Dr. F. Javier Cañada Dr. Sabine André Prof. Dr. Hans‐Joachim Gabius Prof. Dr. Jesús Jiménez‐Barbero Dr. Juan Félix Espinosa Dr. Sonsoles Martín‐Santamaría 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(43):14581-14590
The human lectin galectin‐1 (hGal‐1) translates sugar signals, that is, β‐galactosides, into effects on the level of cells, for example, growth regulation, and has become a model for studying binding of biopharmaceutically relevant derivatives. Bound‐state conformations of Galβ‐C‐(1→3)‐Glcβ‐OMe ( 1 ) and its βGal‐(1→3)‐βGlc‐OMe disaccharide parent compound were studied by using NMR spectroscopy (transferred (TR)‐NOESY data), assisted by docking experiments and molecular dynamics (MD) simulations. The molecular recognition process involves a conformational selection event. Although free C‐glycoside access four distinct conformers in solution, hGal‐1 recognizes shape of a local minimum of compound 1 , the syn‐Φ/syn‐Ψ conformer, not the structure at global minimum. MD simulations were run to explain, in structural terms, the observed geometry of the complex. 相似文献
997.
Sabine Löw Jonathan Becker Christian Würtele Andreas Miska Dr. Christian Kleeberg Prof. Dr. Ulrich Behrens Dr. Olaf Walter Prof. Dr. Siegfried Schindler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(17):5342-5351
Mixing CuCl2 ? 2 H2O with benzylamine in alcoholic solutions led to an extremely colorful chemistry caused by the formation of a large number of different complexes. Many of these different species could be structurally characterized. These include relatively simple compounds such as [Cu(L1)4Cl2] (L1=benzylamine) and (HL1)2[CuCl4]. Most interestingly is the easy formation of two cluster complexes, one based on two cluster units Cu4OCl6(L1)4 connected through one [Cu(L1)2Cl2] complex and one based on a cubane‐type cluster ([Cu4O4](C11H14)4Cl4). Both clusters proved to be highly reactive in a series of oxidation reactions of organic substrates by using air or peroxides as oxidants. Furthermore, it was possible to isolate and structurally characterize ([Cu(L1)Cl]3 and [Cu(benz2mpa)2]CuCl2 (benz2mpa=benzyl‐(2‐benzylimino‐1‐methyl‐propylidene)‐amine), two copper(I) complexes that formed in solution, demonstrating the high redox activity of the cluster systems. In addition, it was possible to solve the molecular structures of the compounds Cu4OCl6(MeOH)4, [Cu(MeOH)2Cl2], [Cu(aniline)2Cl2], and an organic side product (HC13H19NOCl). In fact all determined structures are of a known type but the chemical relation between these compounds could be explained for the first time. The paper describes these different compounds and their chemical equilibria. Some of these complexes seem to be relevant in catalytic oxidation reactions and their reactivity is discussed in more detail. 相似文献
998.
Maurelli S Livraghi S Chiesa M Giamello E Van Doorslaer S Di Valentin C Pacchioni G 《Inorganic chemistry》2011,50(6):2385-2394
The (17)O and (1)H hyperfine interactions of water ligands in the Ti(III) aquo complex in a frozen solution were determined using Hyperfine Sublevel Correlation (HYSCORE) and Pulse Electron Nuclear Double Resonance (ENDOR) spectroscopies at 9.5 GHz. The isotropic hyperfine interaction (hfi) constant of the water ligand (17)O was found to be about 7.5 MHz. (1)H Single Matched Resonance Transfer (SMART) HYSCORE spectra allowed resolution of the hfi interactions of the two inequivalent water ligand protons and the relative orientations of their hfi tensors. The magnetic and geometrical parameters extracted from the experiments were compared with the results of DFT computations for different geometrical arrangements of the water ligands around the cation. The theoretical observable properties (g tensor (1)H and (17)O hfi tensors and their orientations) of the [Ti(H(2)O)(6)](3+) complex are in quantitative agreement with the experiments for two slightly different geometrical arrangements associated with D(3d) and C(i) symmetries. 相似文献
999.
1000.
Strobel S Sperling RA Fenk B Parak WJ Tornow M 《Physical chemistry chemical physics : PCCP》2011,13(21):9973-9977
We report on the successful dielectrophoretic trapping and electrical characterization of DNA-coated gold nanoparticles on vertical nanogap devices (VNDs). The nanogap devices with an electrode distance of 13 nm were fabricated from Silicon-on-Insulator (SOI) material using a combination of anisotropic reactive ion etching (RIE), selective wet chemical etching and metal thin-film deposition. Au nanoparticles (diameter 40 nm) coated with a monolayer of dithiolated 8 base pairs double stranded DNA were dielectrophoretically trapped into the nanogap from electrolyte buffer solution at MHz frequencies as verified by scanning and transmission electron microscopy (SEM/TEM) analysis. First electrical transport measurements through the formed DNA-Au-DNA junctions partially revealed an approximately linear current-voltage characteristic with resistance in the range of 2-4 G? when measured in solution. Our findings point to the importance of strong covalent bonding to the electrodes in order to observe DNA conductance, both in solution and in the dry state. We propose our setup for novel applications in biosensing, addressing the direct interaction of biomolecular species with DNA in aqueous electrolyte media. 相似文献