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排序方式: 共有712条查询结果,搜索用时 640 毫秒
661.
T. Matsuoka T. Fujimoto K. Tanaka S. Miyasaka S. Tajima K. Fujii M. Suzuki M. Tonouchi 《Physica C: Superconductivity and its Applications》2009,469(15-20):982-984
We have developed a terahertz time-domain spectroscopy (THz-TDS) system for reflectivity measurement with a temperature-controllable cryostat. For emission and detection of THz radiation, a Ti:Sapphire pulsed laser and photoconductive antennas are used. Two wire-grid polarizers enable us to carry out the polarized reflectivity measurements. Using our THz-TDS system, we measured the c-axis polarized reflectivity spectra for La2−xSrxCuO4 single crystals (x = 0.10 and 0.13) and observed sharp Josephson plasma edges for both samples below Tc. The reflectivity spectra of the x = 0.10 sample were in good agreement with those reported previously, which confirms the validity of the system. For the x = 0.13 sample, we discuss the anomolous features of the optical spectra. 相似文献
662.
A relativistic virial theorem is derived for atoms in a general manner. The virial ratio consists of the usual V/T term and a correction term W/T, where T, V, and W are the kinetic energy, the potential energy, and correction terms, respectively. Explicit forms of W are presented for four specific nuclear potential models. Numerical calculations for a uniform nuclear charge model show
that the magnitude of the correction term W/T increases with increasing atomic numbers and that it modifies the ratio V/T considerably for atoms with large atomic numbers in particular.
Received: 21 November 2000 / Accepted: 8 January 2001 / Published online: 3 April 2001 相似文献
663.
Shuang‐Jie Tan Junpei Yue Xin‐Cheng Hu Zhen‐Zhen Shen Wen‐Peng Wang Jin‐Yi Li Tong‐Tong Zuo Hui Duan Yao Xiao Ya‐Xia Yin Rui Wen Yu‐Guo Guo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(23):7884-7889
Safety concerns are impeding the applications of lithium metal batteries. Flame‐retardant electrolytes, such as organic phosphates electrolytes (OPEs), could intrinsically eliminate fire hazards and improve battery safety. However, OPEs show poor compatibility with Li metal though the exact reason has yet to be identified. Here, the lithium plating process in OPEs and Li/OPEs interface chemistry were investigated through ex situ and in situ techniques, and the cause for this incompatibility was revealed to be the highly resistive and inhomogeneous interfaces. Further, a nitriding interface strategy was proposed to ameliorate this issue and a Li metal anode with an improved Li cycling stability (300 h) and dendrite‐free morphology is achieved. Meanwhile, the full batteries coupled with nickel‐rich cathodes, such as LiNi0.8Co0.1Mn0.1O2, show excellent cycling stability and outstanding safety (passed the nail penetration test). This successful nitriding‐interface strategy paves a new way to handle the incompatibility between electrode and electrolyte. 相似文献
664.
Daiji Ogata Junpei Yuasa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(51):18595-18599
This work demonstrates a new nonconventional ligand design, imidazole/pyridine‐based nonsymmetrical ditopic ligands ( 1 and 1 S ), to construct a dynamic open coordination cage from nonsymmetrical building blocks. Upon complex formation with Pd2+ at a 1:4 molar ratio, 1 and 1 S initially form mononuclear PdL4 complexes (Pd2+( 1 )4 and Pd2+( 1 S )4) without formation of a cage. The PdL4 complexes undergo a stoichiometrically controlled structural transition to Pd2L4 open cages ((Pd2+)2( 1 )4 and (Pd2+)2( 1 S )4) capable of anion binding, leading to turn‐on anion binding. The structural transitions between the Pd2L4 open cage and the PdL4 complex are reversible. Thus, stoichiometric addition (2 equiv) of free 1 S to the (Pd2+)2( 1 S )4 open cage holding a guest anion ((Pd2+)2( 1 S )4?G?) enables the structural transition to the Pd2+( 1 S )4 complex, which does not have a cage and thus causes the release of the guest anion (Pd2+( 1 S )4+G?). 相似文献
665.
Critical condition of inner cylinder radius for sustaining rotating detonation waves in rotating detonation engine thruster 总被引:1,自引:0,他引:1
Akira Kawasaki Tomoya Inakawa Jiro Kasahara Keisuke Goto Ken Matsuoka Akiko Matsuo Ikkoh Funaki 《Proceedings of the Combustion Institute》2019,37(3):3461-3469
We describe the critical condition necessary for the inner cylinder radius of a rotating detonation engine (RDE) used for in-space rocket propulsion to sustain adequate thruster performance. Using gaseous C2H4 and O2 as the propellant, we measured thrust and impulse of the RDE experimentally, varying in the inner cylinder radius ri from 31 mm (typical annular configuration) to 0 (no-inner-cylinder configuration), while keeping the outer cylinder radius (ro = 39 mm) and propellant injector position (rinj = 35 mm) constant. In the experiments, we also performed high-speed imaging of self-luminescence in the combustion chamber and engine plume. In the case of relatively large inner cylinder radii (ri = 23 and 31 mm), rotating detonation waves in the combustion chamber attached to the inner cylinder surface, whereas for relatively small inner cylinder radii (ri = 0, 9, and 15 mm), rotating detonation waves were observed to detach from the inner cylinder surface. In these small inner radii cases, strong chemical luminescence was observed in the plume, probably due to the existence of soot. On the other hand, for cases where ri = 15, 23, and 31 mm, the specific impulses were greater than 80% of the ideal value at correct expansion. Meanwhile, for cases ri = 0 and 9 mm, the specific impulses were below 80% of the ideal expansion value. This was considered to be due to the imperfect detonation combustion (deflagration combustion) observed in small inner cylinder radius cases. Our results suggest that in our experimental conditions, ri = 15 mm was close to the critical condition for sustaining rotating detonation in a suitable state for efficient thrust generation. This condition in the inner cylinder radius corresponds to a condition in the reduced unburned layer height of 4.5–6.5. 相似文献
666.
Thomas Delzeit Luca Carmignani Tsuneyoshi Matsuoka Subrata Bhattacharjee 《Proceedings of the Combustion Institute》2019,37(3):3203-3209
This systematic experimental study measures the effect of flame propagation along vertical edges on the overall downward spread of flames using Polymethyl Methacrylate (PMMA). Samples with a wide range of regular cross-sections – from triangular through octagonal – as well as irregular ones, have been used to test a large variation of internal angles. A MATLAB-based tool was used to calculate instantaneous spread rate for central and edge flames. The edge flame is shown to significantly enhance the spread rate, as much as five times, in respect to samples with no edges. This amplification is shown to depend primarily on the internal angle at the edge (the smaller the angle, the faster the flame) and fuel thickness, and not on other factors such as aspect ratio or cross-sectional area. Using a phenomenological argument, the edge propagation rate is correlated to the spread rate over an equivalent cylindrical fuel (the limiting shape with infinite edges) with an effective radius obtained from the geometry of the edges and the diffusion length scale of the solid phase. A formula for flame spread over cylindrical fuel from the literature is used to link the new results to existing models. Both thick and thin limits are shown to encompass the wide range of three-dimensional spread rate data within the effective radius (the independent variable), which can be determined from the known parameters. Based on these results, different types of cross-sectional areas can be sorted in the order of their inherent fire safety characteristics. 相似文献
667.
Hisayuki Nakatani Hitoshi Matsuoka Shoutarou Suzuki Toshiaki Taniike Liu Boping Minoru Terano 《Macromolecular Symposia》2007,257(1):112-121
Summary: Temperature rising elution fractionation (TREF) has been regarded as a powerful technique for study of semicrystalline polymers. In this paper, two examples of unique applications of TREF were introduced. One was the study on the influence of extraction of internal donor on the variation of isospecific active sites of a MgCl2- supported Ziegler catalyst, and the other was the estimation of the relationship between polymer micro-tacticity and degradation rate of isotactic polypropylene (iPP). The former example revealed the conversion from high to low isospecific site by the extraction of internal donors, whereas the latter showed a negative correlation between the level of isotacticity and the degradation rate. These results demonstrated that TREF was useful in these research applications. 相似文献
668.
Y. Yoshida M. Matsuoka S. C. Moon H. Mametsuka E. Suzuki M. Anpo 《Research on Chemical Intermediates》2000,26(6):567-574
The photocatalytic decomposition of liquid water on Pt-loaded TiO2 (Pt/TiO2) catalysts was investigated. The results obtained by XPS and XRD measurements of the catalysts as a function of the calcination
temperature as well as the photocatalytic decomposition reactions of H2O clearly indicate that controlling the oxidation state of Pt as well as the amount of loaded Pt species are both important
factors in the design of water-splitting photocatalysts having high efficiency and stoichiometry. 相似文献
669.
Naoki Suzuki Akimitsu Takamori Junpei Baba Junichi Matsuda Toshio Hyodo Yasushi Okamoto Hiroshi Miyagi 《Radiation Physics and Chemistry》2000,58(5-6):593-596
Positron lifetime spectra for general purpose polystyrene (GPPS), polybutadiene rubber (PBR), and their copolymers, styrenebutadiene rubber (SBR) and high impact polystyrene (HIPS) have been measured. It has been found that the free volumes in the copolymers are smaller than the average over the individual polymers, due to the interfacial interaction between the styrene and rubber phases. A long-lived component with a mean lifetime of about 123 ns was observed in the spectrum for deformed HIPS, showing the existence of ortho-positronium (o-Ps) in the deformation induced crazes. 相似文献
670.
T. Nakano J. K. Ahn H. Ejiri M. Fujiwara T. Hotta N. Matsuoka T. Matsumura T. Mibe M. Nomachi H. Toki C. W. Wang S. C. Wang H. Kawai T. Ooba T. Iwata Y. Miyachi T. Toyama A. Wakai K. Hicks H. Akimune Y. Asano Y. Sugaya S. Dat N. Kumagai Y. Ohashi H. Toyokawa K. Imai M. Yosoi A. Ichikawa T. Kishimoto A. Sakaguchi M. Sumihama S. Makino H. Shimizu 《Nuclear Physics A》2000,670(1-4):332-339
The GeV photon beam at SPring-8 is produced by backward-Compton scattering of laser photons from 8 GeV electrons. The maximum energy of the photon will be above 3 GeV, and the beam intensity will be 107 photons/sec. Polarization of the photon beam will be 100 % at the maximum energy with fully polarized laser photons. We report the outline of the quark nuclear physics project with this high-quality high-intensity beam. 相似文献