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431.
Hirotaka Ogawa Akinori Kan Makoto Ohsashi 《Physica C: Superconductivity and its Applications》2008,468(6):447-452
The superconductivity of ZnO-doped (Bi, Pb)-2223 thick film on the Ni and NiO substrates, which was prepared by the spray deposition technique with cold forging, was investigated by characterizing the critical current density (Jc), the critical temperature (Tc), the orientation factor (f), and the microstructure of the film. The thickness of the thick film prepared by the spray deposition method was approximately 10 μm. The maximum Jc value of (Bi, Pb)-2223 film on NiO substrate was approximately 2200 A/cm2 (Ic = 110 mA) when the film was sintered at 865 °C for 1 h with a cooling rate of 0.5 °C/min from 865 °C to 650 °C; in the case of Ni substrate, a maximum Jc value of approximately 2000 A/cm2 (Ic = 100 mA) was obtained for the (Bi, Pb)-2223 thick film when a cooling rate was 3 °C/min. Such a difference in the Jc values of (Bi, Pb)-2223 thick film on Ni and NiO substrates is attributed to the presence of reaction layer at the (Bi, Pb)-2223 and substrate interface. In addition, the variations in the orientation factor of (Bi, Pb)-2223 thick film on NiO substrate related to those of Jc values. The Jc values of (Bi, Pb)-2223 film on NiO substrate with ZnO doping extremely depended on the amount of ZnO doping and the 0.5 wt% ZnO-doped (Bi, Pb)-2223 thick film deposited on NiO substrate, which was sintered at 835 °C for 1 h in air with a cooling rate of 1 °C/min, showed a Jc value of approximately 1200 A/cm2 (Ic = 60 mA). Thus, it is considered that a small amount of ZnO doping was effective in lowering the sintering temperature of (Bi, Pb)-2223 thick film, resulting the improvement in the intragranular weak bonding or Josephson junction. 相似文献
432.
Yanagida H 《Ultrasonics sonochemistry》2008,15(4):492-496
The sonochemical luminescence intensity from luminol was measured at a sampling rate of several kilohertz. This was noted at three different periods: first, the latent period in which no light emission occurs at all; second, the increased emission period from the start of light emission to the time when a steady state is reached; and third, the steady state period in which light emission occurs at the steady state value. When irradiated with ultrasound of different intensities, the times of the latent period and increased emission period are shorter for higher ultrasound intensities. To know how the dissolved oxygen content is involved in early-stage cavitation growth, an experiment was conducted using solutions with varying dissolved oxygen contents from 100% to 37%. For dissolved air content of 50% or less, it was found that the latent period was 30 times longer in a saturated condition. It was also found that the increased emission period was 10 times longer. However, the emission intensity in the steady state did not change at all even when the initial dissolved gas concentration of the sample was changed. From this, it was found that the reuse of collapsed bubbles takes place efficiently in the steady state. Dissolved oxygen was reduced by the use of a vacuum pump and by the degassing action of ultrasound, and it was discovered that the behavior of transient emission differed for the two ways of degassing. 相似文献
433.
434.
Prof. Ming-Shui Yao Prof. Ken-ichi Otake Jiajia Zheng Masahiko Tsujimoto Dr. Yi-Fan Gu Lu Zheng Dr. Ping Wang Dr. Shivanna Mohana Dr. Mickaele Bonneau Tomoyuki Koganezawa Tetsuo Honma Hirotaka Ashitani Shogo Kawaguchi Prof. Yoshiki Kubota Prof. Susumu Kitagawa 《Angewandte Chemie (International ed. in English)》2023,62(35):e202308990
A one-stone, two-bird method to integrate the soft porosity and electrical properties of distinct metal–organic frameworks (MOFs) into a single material involves the design of conductive-on-insulating MOF (cMOF-on-iMOF) heterostructures that allow for direct electrical control. Herein, we report the synthesis of cMOF-on-iMOF heterostructures using a seeded layer-by-layer method, in which the sorptive iMOF core is combined with chemiresistive cMOF shells. The resulting cMOF-on-iMOF heterostructures exhibit enhanced selective sorption of CO2 compared to the pristine iMOF (298 K, 1 bar, S from 15.4 of ZIF-7 to 43.2–152.8). This enhancement is attributed to the porous interface formed by the hybridization of both frameworks at the molecular level. Furthermore, owing to the flexible structure of the iMOF core, the cMOF-on-iMOF heterostructures with semiconductive soft porous interfaces demonstrated high flexibility in sensing and electrical “shape memory” toward acetone and CO2. This behavior was observed through the guest-induced structural changes of the iMOF core, as revealed by the operando synchrotron grazing incidence wide-angle X-ray scattering measurements. 相似文献
435.
Hirotaka Nakajima Kaiji Uchida Dr. Takefumi Yoshida Dr. Yoji Horii Dr. Tetsu Sato Zhang Luming Dr. Satoshi Yamashita Dr. Yasuhiro Nakazawa Dr. Verdad C. Agulto Dr. Makoto Nakajima Dr. Brian K. Breedlove Dr. Masahiro Yamashita Dr. Hiroaki Iguchi Dr. Shinya Takaishi 《Chemphyschem》2023,24(4):e202200618
We report the water adsorption/desorption behavior and dynamic magnetic properties of the Pt−Cl chain complex [{[Pt(en)2][PtCl2(en)2]}3][{(MnCl5)Cl3}2] ⋅ 12H2O ( 1 ). Upon heating 1 in a vacuum, we obtained the dehydrated form [{[Pt(en)2][PtCl2(en)2]}3][{(MnCl5)Cl3}2] ( 1DH ). The framework structures of 1 and 1DH are identical, and both complexes underwent slow magnetic relaxation. However, the magnetic relaxation times for 1DH were shorter than those for 1 , meaning that the dynamic magnetic properties were controlled upon water vapor adsorption/desorption. From detailed analyses of the dynamic magnetic behavior, a phonon-bottleneck effect contributes to the magnetic relaxation processes. We discuss the mechanism for the changes in the magnetic relaxation processes upon dehydration in terms of the heat capacity and thermal conductivity. 相似文献
436.
Prof. Dr. Hongyao Zhou Hirotaka Inoue Mizuha Ujita Prof. Dr. Teppei Yamada 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(2):e202213449
Thermocells are a thermoelectric conversion technology that utilizes the shift in an electrochemical equilibrium arising from a temperature difference. This technology has a long history; however, its low conversion efficiency impedes its practical usage. Recently, an increasing number of reports have shown drastic improvements in thermoelectric conversion efficiency, and thermocells could arguably represent an alternative to solid thermoelectric devices. In this Minireview, we regard thermocells as molecular systems consisting of successive molecular processes responding to a temperature change to achieve energy generation. Various molecular technologies have been applied to thermocells in recent years, and could stimulate diverse research fields, including supramolecular chemistry, physical chemistry, electrochemistry, and solid-state ionics. These research approaches will also provide novel methods for achieving a sustainable society in the future. 相似文献