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991.
Pter Vmosi Keiya Matsuo Tsuguya Masuda Kohei Sato Tetsuo Narumi Kazuhiro Takeda Nobuyuki Mase 《Chemical record (New York, N.Y.)》2019,19(1):77-84
Generally, the flow method has the advantage of a precise control over the reaction parameters and a facile modification of the reaction conditions, while a continuous flow microwave reactor allows for the quick optimization of reaction conditions owing to the rapid uniform heating. In this study, we developed a “9+4+1 method” to optimize reaction conditions based on comprehensive reaction analysis using a flow microwave reactor. The proposed method is expected to contribute to the synthesis of various fine and bulk chemicals by reducing cost and wastage, and by conserving time. 相似文献
992.
Mizuho Kondo Taku Yamoto Seiya Miura Mayuko Hashimoto Chitoshi Kitamura Nobuhiro Kawatsuki 《化学:亚洲杂志》2019,14(3):471-479
In this study, mechanochromic luminescence was induced in a complex of mechano‐inactive compounds. Dye/acid complexes containing the same π‐conjugated backbones were prepared. While the luminophore showed blue and red shifts in photoluminescence spectra when combined with different acids by grinding, it exhibited slight mechanoresponsiveness itself. Also, compounds with similar molecular backbones to the dye/acid complex were synthesized to clarify the color change mechanism. The compounds showed both blue and red shifts in photoluminescence and diffuse reflectance spectra upon grinding, indicating that mechanochromic luminescence in the hydrogen‐bonded complex is like its monomeric analogue and that aggregation structure plays an important role in mechanoresponsive behavior rather than the π‐conjugated structure. It was shown that a color change can be mechanically induced by imitating the solid‐state aggregation structure of other mechanoresponsive compounds without synthetic modification. 相似文献
993.
Takashi Takeda Masataka Ozawa Tomoyuki Akutagawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(30):10453-10460
There is a limited number of reports on mechanically responsive molecular crystals, including thermo‐responsive and light‐responsive crystals. Rigid ordered molecular crystals with a close‐packing structure are less able to accept distortion, which hampers the development of such molecular crystals. The thermosalient effect, or “crystal jumping”, refers to a thermo‐responsive system that converts heat into mechanical force by thermally induced phase transition. While they have recently attracted attention as potential highly efficient molecular actuators, less than two dozens of thermosalient molecular crystals have been reported to date, and the design of such molecules as well as how they assemble to express a thermosalient effect are unknown. Herein, we demonstrate how the cooperative molecular motion of twisted π units could serve to develop a thermo‐responsive jumping molecular crystal with a hydrogen‐bonded organic framework (HOF) of tetra[2,3]thienylene tetracarboxylic acid ( 1 ). The cooperative change in the molecular structure triggered by the desolvation of THF in the channel of the HOF structure induced not only a change in the structure of HOF but also mechanical force. Hydrogen bonding interactions contributed significant thermal stability to maintain the HOF assembly even with a dynamic structural change. 相似文献
994.
A new phase with a 10H-type long-period stacking (LPS) structure was found in an Mg75Al10Y15 alloy annealed at 823?K. The LPS structure in the Mg75Al10Y15 alloy annealed at 823?K for 2?h has an ordered arrangement of L12-type structural Al6Y8 clusters on the two-dimensional plane parallel to the c-plane of hexagonal Mg lattice and a disordered arrangement along the c-axis, whereas a perfectly ordered structure along the c-axis, which has a period with two times of that of the 10H-type LPS structure, was established by annealing at 823?K for 24?h. The structural model of the ordered LPS phase is proposed by high-resolution images taken with a Cs-corrected scanning transmission electron microscope and also electron diffraction patterns. 相似文献
995.
R. Uchiyama K. Kusagawa K. Hanai N. Imanishi A. Hirano Y. Takeda 《Solid State Ionics》2009,180(2-3):205-211
Polyethylene oxide (PEO)-based electrolytes were crosslinked using electron beam (EB) irradiation. The gel contents of a polymer film were increased after irradiation doses of 0, 140, 280, and 420 kGy, with ionic conductivities of 0.831, 1.55, 6.08, and 7.95 (× 10? 5) S cm? 1 at 40 °C, respectively. The slight decrease in conductivity at higher temperatures after irradiation is due to the retardation of polymer motion by crosslinking. The electrolyte with higher EB dose amount exhibits higher conductivity due to stabilization of the amorphous state. The EB crosslinking with a co-bridging agent shows enhanced conductivities of 4.71, 6.59, and 7.18 (× 10? 5) S cm? 1 at 40 °C, after irradiation with 140, 280, and 420 kGy. Addition of the co-bridging agent is effective for developing a crosslinked structure with a smaller EB dose. Tensile strength becomes two to three times higher with irradiation compared to the non-treated polymer. Combination of the EB technique with a co-bridging agent is a simple and effective method to prepare strong dry polymer electrolyte films with improved room temperature conductivity. 相似文献
996.
Takahiro Natsume Tomoyasu Amano Yasuo Takehara Takashi Ichihara Kan Takeda Hajime Sakuma 《Magnetic resonance imaging》2009
Purpose
The objective of this study is to determine regional left ventricle (LV) function and temporal heterogeneity of LV wall contraction by analyzing regional time–volume curve (TVC) after Fourier fitting and to assess altered systolic and diastolic functions and temporal indices of myocardial contraction in infarcted segments in comparison with noninfarcted myocardium in patients with myocardial infarction (MI).Methods
Steady-state cine magnetic resonance (MR) and late gadolinium-enhanced (LGE) MR images were acquired using a 1.5-T MR system in 60 patients with MI. Regional LV function was determined by analyzing regional TVC in 16 segments. The fitted regional TVC was generated by Fourier curve fitting with five harmonics. Regional LV ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR), time to end-systole and time to peak filling (TPF) were determined from TVC and the first derivative curve.Results
On LGE MR imaging (MRI), MI was observed in 307 of 960 segments (32.0%). Regional EF and PER averaged in LGE segments were 49.3±14.5% and 2.83±0.65 end-diastolic volume (EDV)/s, significantly lower than those in normal segments (66.7±11.9% and 3.63±0.60 EDV/s, P<.001 and P<.01, respectively). In addition, regional PFR, an index of diastolic function, was significantly reduced in LGE segments (1.94±0.54 vs. 2.86±0.68 EDV/s, P<.01). Time to end-systole and TPF were significantly greater in LGE segments (380.2±57.6 and 169.3±45.4 ms) than in normal segments (300.9±55.1 and 132.3±43.0 ms, P<.01 and P<.01, respectively).Conclusions
Analysis of regional TVC on cine MRI after Fourier fitting allows quantitative assessment of regional systolic and diastolic LV functions and temporal heterogeneity of LV wall contraction in patients with MI. 相似文献997.
Shuichi Wakimoto Hiroyuki Kimura Mamoru Fukunaga Keisuke Nishihata Masayasu Takeda Kazuhisa Kakurai Yukio Noda Yoshinori Tokura 《Physica B: Condensed Matter》2009,404(17):2513
Polarized neutron diffraction experiments have been performed on multiferroic materials RMn2O5 (R=Ho, Er) under electric fields in the ferroelectric commensurate (CM) and the low-temperature incommensurate (LT-ICM) phases, where the former has the highest electric polarization and the latter has reduced polarization. It is found that, after cooling in electric fields down to the CM phase, the magnetic chirality is proportional to the electric polarization. Also we confirmed that the magnetic chirality can be switched by the polarity of the electric polarization in both the CM and LT-ICM phases. These facts suggest an intimate coupling between the magnetic chirality and the electric polarization. However, upon the transition from the CM to LT-ICM phase, the reduction of the electric polarization is not accompanied by any reduction of the magnetic chirality, implying that the CM and LT-ICM phases contain different mechanisms of the magnetoelectric coupling. 相似文献
998.
The stability of the current across Si nanochain network is investigated using a micromanipulator in a scanning electron microscope system. We confirm that the current is dominated by the tunneling of electrons between Si nanoparticles. We observe large current fluctuations at a high bias voltage, while the current is stable at a relatively low bias voltage. The origin of the fluctuation is discussed in terms of percolation. 相似文献
999.
The subband dispersions in the Si(1 1 1) p-type inversion layers induced by Pb and Ga adsorbed surface structures were measured by angle-resolved photoemission spectroscopy (ARPES). The surface structures used here were and Si(1 1 1)6.3 × 6.3-Ga. is a new surface phase found in this study. Because it is significant in our study to investigate potential effects of surface superstructures on the hole subband dispersion, we investigated the subband energy levels quantitatively comparing them with those calculated using the triangular approximation. It was found that the energy separation of the adjacent subband quantum levels in the inversion layers induced by gallium adsorption does not follow the triangular approximation. The possible band bending shape was proposed to explain the quantum level spacing of the subbands in Ga-induced inversion layers. 相似文献
1000.
Wakasugi M Emoto T Furukawa Y Ishii K Ito S Koseki T Kurita K Kuwajima A Masuda T Morikawa A Nakamura M Noda A Ohnishi T Shirai T Suda T Takeda H Tamae T Tongu H Wang S Yano Y 《Physical review letters》2008,100(16):164801
A novel internal target has been developed, which will make electron scattering off short-lived radioactive nuclei possible in an electron storage ring. An "ion trapping" phenomenon in the electron storage ring was successfully utilized for the first time to form the target for electron scattering. Approximately 7 x 10(6) stable 133Cs ions were trapped along the electron beam axis for 85 ms at an electron beam current of 80 mA. The collision luminosity between the stored electrons and trapped Cs ions was determined to be 2.4(8) x 10(25) cm(-2) s(-1) by measuring elastically scattered electrons. 相似文献