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121.
Quinone dimers connected with acetylene (QAQ) and diacetylene linkages (QAAQ) have been synthesized and their structure and electronic properties studied. X-ray analysis, DFT calculations, and UV-vis measurements showed that, unlike directly connected quinone dimers (QQ), they had planar and thus efficiently extended π conjugation systems. The respective reduction potentials of QAQ and QAAQ were considerably raised, and QAQ thereby behaved as a mild oxidizing agent. 相似文献
122.
Ohkawa K Hayashi S Kameyama N Yamamoto H Yamaguchi M Kimoto S Kurata S Shinji H 《Macromolecular bioscience》2009,9(1):79-92
A synthetic route is described for collagen-like polypeptides constructed from O-phospho-L-hydroxyproline [Hyp(PO(3)H(2))] residues. Using the synthetic polypeptides and a natural protein, gelatin, fine fibers and their network structures (ESNWs) were prepared via electrospinning. The composite ESNWs can induce the mineralization of calcium phosphate. The phosphoryl groups of the Hyp(PO(3)H(2)) residues affect both the crystalline phase and amount of the calcium phosphate, depending on the chemical structure in the repeating sequence. The composite ESNWs can be developed as a biocompatible replacement of the extracellular matrix of hard tissues, and thus can be applied as dental materials for restoration of dental cavities or as a sealant for pits and fissures. 相似文献
123.
Hitoshi Sugiyama Chiriki Watanabe Naoto Kato 《International Journal of Computational Fluid Dynamics》2013,27(8):335-348
A numerical analysis has been performed for a developing turbulent flow in a rotating U-bend of strong curvature with rib-roughened walls using an anisotropic turbulent model. In this calculation, an algebraic Reynolds stress model is used to precisely predict Reynolds stresses, and a boundary-fitted coordinate system is introduced as a method of coordinate transformation to set the exact boundary conditions along the complicated shape of U-bend with rib-roughened walls. Calculated results for mean velocity and Reynolds stresses are compared to the experimental data in order to validate the proposed numerical method and the algebraic Reynolds stress model. Although agreement is certainly not perfect in all details, the present method can predict characteristic velocity profiles and reproduce the separated flow generated near the outer wall, which is located just downstream of the curved duct. The Reynolds stresses predicted by the proposed turbulent model agree well with the experimental data, except in regions of flow separation. 相似文献
124.
125.
Watanabe Hayato Omura Takuya Okaichi Naoto Kano Masanori Sasaki Hisayuki Arai Jun 《Optical Review》2022,29(4):366-374
Optical Review - Light field displays can display three-dimensional (3D) images with smooth motion parallax without the use of special glasses, by reproducing light ray information from objects.... 相似文献
126.
The combination of carbaboranylmercuric chloride (new type of bulky Lewis acid) and silver triflate efficiently catalyzes cycloisomerization of 1,3-dienes at room temperature. The catalytic system gives allyl-substituted azacycles and cycloalkanes in excellent yields with high to complete regioselectivity. 相似文献
127.
Despite significant advances in the catalytic direct arylation of heteroarenes, the application of this reaction to pyridines has been met with limited success. An oxidative nucleophilic arylation strategy has been developed to overcome this problem. Pyridine, pyrazine, quinolone, and related electron‐deficient N‐heteroarenes can be arylated at the most electrophilic site using the developed nickel‐catalyzed reaction. This protocol serves as a complementary method to catalytic direct arylation reactions. 相似文献
128.
We used hybrid density-functional calculations to clarify the effect of substituting chromium for titanium (Cr(Ti)) on photocatalytic activities of Cr-doped SrTiO(3). A singly negative Cr(Ti)?, which is relevant to a lower oxidation state of Cr, is advantageous for the visible light absorption without forming electron trapping centers, while other charge states are inactive for the photocatalytic reaction. Stabilizing the desirable charge state (Cr(Ti)?) is feasible by shifting the Fermi level towards the conduction band. Our theory sheds light on the photocatalytic properties of metal-doped semiconductors. 相似文献
129.
Spectroscopic investigations have been performed for the oxidized forms of two quadruple-decker phthalocyanine complexes in order to clarify the electronic structures of multiply stacked π-systems. Up to three-electron-oxidized species were isolated by using phenoxathiin hexachloroantimonate as the oxidant. As the oxidations proceed, the Q-bands in the visible region shift bathochromically along with the clear isosbestic points. The one- and three-electron-oxidized species exhibited typical π-radical signals in the ESR spectra, while the neutral and two-electron oxidized species gave no indication of the presence of π-radicals. The electronic transitions observed for the oxidized species reach even into the so-called fingerprint region in IR spectroscopy (~1000 cm(-1)). With the aid of theoretical calculations, these bands can be assigned to the π-π* transitions. Our results provide new insights into π-electronic systems having exceptionally small MO energy gaps. 相似文献
130.
Tomoyuki Kobayashi Junji Yamamoto Takao Hirajima Hidemi Ishibashi Naoto Hirano Yong Lai Vladimir S. Prikhod'ko Shoji Arai 《Journal of Raman spectroscopy : JRS》2012,43(8):1126-1133
To assess the ability of densimetry for CO2 fluid in CO2 inclusions, we compare two methods, microthermometry and Raman microspectroscopic densimetry for CO2. The comparative experiment was performed for nine CO2 inclusions in three mantle xenoliths. The results are as follows: (1) microthermometry precisely determines CO2 density with the range of 0.65 to 1.18 g/cm3 compared with Raman microspectroscopic densimetry; (2) CO2 density obtained by Raman microspectroscopic densimetry is fairly consistent with that by microthermometry; (3) it is hard to determine CO2 density in CO2 inclusion with diameter of less than around 3 µm using microthermometry; and (4) microthermometry can be applied only to the CO2 inclusion whose CO2 density ranges from around 0.65 to 1.18 g/cm3, whereas the Raman microspectroscopic densimetry is applicable to CO2 density ranging from 0.1 to 1.24 g/cm3. The above features carry the potential for estimation of depth origin of mantle‐derived rocks. The depth where the rocks were trapped by host magma can be estimated using both geothermometric data and CO2 fluid density in CO2 inclusions in the rocks. Typical precisions of density of CO2 in CO2 inclusions obtained by the Raman microspectroscopic densimetry (~0.01 g/cm3) and by the microthermometry (< 0.001 g/cm3) correspond to uncertainties in the depth origin of 2.4 km and < 1.7 km, respectively, at 1000 ± 50 °C. In case of the mantle under 750–1250 °C and 1 GPa, the CO2 fluid has a density ranging from 1.06 g/cm3 to 1.21 g/cm3, which are well measured by the Raman microspectroscopic densimetry. Combination of both densimetries for CO2 in mantle minerals elucidates the deep structure of the Earth. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献