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941.
942.
Renata Drozdzak Naoki Nishioka Gilles Recher Francis Verpoort 《Macromolecular Symposia》2010,293(1):1-4
Summary: Advances in design of latent ruthenium phenylindenylidene catalysts bearing salicylaldimine ligands for ring-opening metathesis polymerization are described. The presence of the substituents in ortho position in N-aryl ring of salicylaldimine ligand has been found to be the main factor determining the catalyst stability. The best of the studied catalysts after acid activation offers activity comparable to that of the dichloride systems in ring-opening metathesis polymerization of DCPD, while maintaining very high stability in the monomer solution. 相似文献
943.
Zhifeng Ma Kasumi Ukaji Naoki Nakatani Hiroshi Fujii Masahiko Hada 《Journal of computational chemistry》2019,40(19):1780-1788
The effects of peripheral fluorine atoms on epoxidation reactions of ethylene by oxoiron(IV) porphyrin cation radical complex in the quartet and sextet spin multiplicities are systematically investigated using the DFT method. The overall reaction routes are determined using a model system of ethylene and Fe(IV)OCl-porphyrin with substituted fluorine atoms. By obtaining the energy diagrams and electron- and spin-density difference contour maps of the transition states and intermediate compounds, we confirm that the electron-withdrawing by peripheral fluorine atoms enhances the reactivity as the number of fluorine atoms increases, as is observed experimentally. The intersystem crossing between the quartet and sextet spin multiplicities is discussed by means of the intrinsic reaction coordinate method. We conclude that the rate-determining step is located at the first transition state (TS1) for the activation of CC and FeO bonds, and the ground electronic state changes from quartet to sextet around the TS1. © 2019 Wiley Periodicals, Inc. 相似文献
944.
Waka Nakanishi Shohei Saito Naoki Sakamoto Akihiro Kashiwagi Shigehiro Yamaguchi Hideki Sakai Katsuhiko Ariga 《化学:亚洲杂志》2019,14(16):2869-2876
The air–water interface, which is the boundary of two phases with a large difference in polarity, gives a distinct environment compared with bulk water or air. Since the interface provides a field for various biomolecules to work, it is important to understand the molecular behaviors at the interface. Here, polarity‐independent flapping viscosity probes (FLAP) equipped with hydrophobic/hydrophilic substituents have been synthesized and studied at the air–water interface. In situ fluorescence (FL), which is related to the internal motion and orientation, of three different FLAPs were investigated at the interface, and the internal motion of the molecule was indicated to be suppressed at the interface. In addition, the molecular response was compared with that of conventional viscosity probes (molecular rotors), which indicates the different behaviors of FLAP probably due to the distinct molecular orientation as well as molecular motion. 相似文献
945.
Quantum information capsule and information delocalization by entanglement in multiple-qubit systems
Where do entangled multiple-qubit systems store information? For information injected into a qubit, this question is nontrivial and interesting since the entanglement delocalizes the information. So far, a common picture is that of a qubit and its purification partner sharing the information quantum mechanically. Here, we introduce a new picture of a single qubit in the correlation space, referred to as quantum information capsule (QIC), confining the information perfectly. This picture is applicable for the entangled multiple-qubit system in an arbitrary state. Unlike the partner picture, in the QIC picture, by swapping the single-body state, leaving other subsystems untouched, the whole information can be retrieved out of the system. After the swapping process, no information remains in the system. 相似文献
946.
Yushin Shibuya Naoki Nakagawa Naoki Miyagawa Toyoko Suzuki Kentaro Okano Atsunori Mori 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(28):9647-9650
The unprecedented synthesis of regioregular head‐to‐tail‐type poly(1,4‐arylene)s bearing different substituents at the 2‐ and 5‐positions is described. They were prepared by the polymerization of 2,5‐disubstituted bromo(chloro)arylenes by selective halogen–metal exchange with a Grignard reagent and subsequent cross‐coupling polymerization with a nickel catalyst [NiCl2(dppp)]. Formation of the regioregular poly(1,4‐arylene)s were confirmed by NMR spectroscopy, and showed remarkable differences to those polymers having uncontrolled regioregularity. Polymerization of bromo(chloro)arylenes with a chiral alkoxy substituent also led to the regioregular head‐to‐tail‐type polyarylene, which demonstrated circular dichroism, thus suggesting formation of a structure with higher‐order regularity. 相似文献
947.
Tomonori Ito Naoki Takasu Toru Akiyama Kohji Nakamura 《Applied Surface Science》2009,256(4):1218-1221
The atomic arrangements in zinc blende structured GaNxAs1−x thin films coherently grown on V-grooved substrates are theoretically investigated using empirical interatomic potentials and Monte Carlo simulation. The resultant atomic arrangements in GaNxAs1−x strongly depend on concentration x and substrate lattice parameter asub. Surface segregation of As or N is mainly found in GaNxAs1−x with large lattice mismatch to the substrate. On the other hand, the novel atomic arrangements such as layered segregation or ordered structure are found in GaNxAs1−x at the specific region such as (x, asub) = (0.5, 5.3), (0.3, 5.3), and (0.3, 5.1). This specific region corresponds to that with negative excess energy and with sufficient N and As atoms remaining in thin film layers even after their surface segregation. The formation of the novel atomic arrangements is discussed in terms of bond lengths in the surface layers. These results suggest that various novel atomic arrangements in alloy semiconductor thin films appear depending on x and asub which control degree of lattice constraint. 相似文献
948.
Tomotaka Shimoyama Takeo Tojo Hitoshi Kawaji Tooru Atake Hiroshi Fukazawa Naoki Igawa 《Solid State Ionics》2009,180(6-8):560-562
Heat capacity and neutron diffraction measurements were carried out to determine the location of protons in the crystal of proton conducting perovskite oxide BaZr0.8Sc0.2O2.9. The heat capacity of proton- and deuteron-dissolved BaZr0.8Sc0.2O2.9 showed a slight difference from that of the dry sample. It indicates that the librational motion of the OH(OD) group is not excited below room temperature. The neutron diffraction experiments on the deutron dissolved sample indicate that the deuteron exists near the 12h site. 相似文献
949.
Yuansen Tang Naoki Haruta Akiyoshi Kuzume Kimihisa Yamamoto 《Molecules (Basel, Switzerland)》2021,26(16)
Direct detection and characterisation of small materials are fundamental challenges in analytical chemistry. A particle composed of dozens of metallic atoms, a so-called subnano-particle (SNP), and a single-atom catalyst (SAC) are ultimate analysis targets in terms of size, and the topic is now attracting increasing attention as innovative frontier materials in catalysis science. However, characterisation techniques for the SNP and SAC adsorbed on substrates requires sophisticated and large-scale analytical facilities. Here we demonstrate the development of an ultrasensitive, laboratory-scale, vibrational spectroscopic technique to characterise SNPs and SACs. The fine design of nano-spatial local enhancement fields generated by the introduction of anisotropic stellate-shaped signal amplifiers expands the accessibility of small targets on substrates into evanescent electromagnetic fields, achieving not only the detection of isolated small targets but also revealing the effects of intermolecular/interatomic interactions within the subnano configuration under actual experimental conditions. Such a development of “in situ subnano spectroscopy” will facilitate a comprehensive understanding of subnano and SAC science. 相似文献
950.
The surface of β-Ga2O3 (1 0 0) single crystal grown with floating zone method was treated by chemical-mechanical-polishing (CMP) for 30-120 min followed by annealing in oxygen atmosphere at temperature 600-1100 °C for 3-6 h. The evolution of the step arrangement was investigated with reflection high energy electron diffraction and atomic force microscopy. Atomically smooth surfaces with atomic step and terrace structure of β-Ga2O3 substrates were successfully obtained after just CMP treatment as well as CMP treatment and post annealing at 1100 °C for 3 h. The uniform step height was 0.57 nm, and smooth terrace width was 100 nm, where the misorientation angle was about 0.36°. The obtained atomically smooth surface provides a potential application for the high-quality epitaxial film growth. 相似文献