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991.
Shigeo Nakamura Masato Amano 《Journal of polymer science. Part A, Polymer chemistry》1997,35(16):3359-3363
Nitrogen-containing cellulose derivatives hydrazinodeoxycellulose (HDC) and carboxyalkyl hydrazinodeoxycelluloses (α- and β-CAHDCs) were prepared from 6-chlorodeoxycellulose (CDC). Their adsorption of divalent transition metal ions was determined from dilute aqueous solutions and compared with that of aminoalkyl celluloses (AmACs) reported previously. HDC scarcely adsorbs metal ions in the pH range of 1–2, whereas α- and β-CAHDCs adsorb metal ions in this pH range. However, the adsorption of metal ions on HDC increases rapidly with increasing pH and HDC more effectively adsorbs metal ions than α- and β-CAHDCs in weakly acidic conditions. The ability to adsorb Cu2+ ions was in the order of AmAC (carbon number in the diamine moiety m = 2) > HDC > α-CAHDC > β-CAHDC in the weakly acidic region. These adsorbents selectively adsorb Cu2+ ions from the solutions containing other metal ions such as Mn2+, Co2+, and Ni2+, and the Irving–Williams series is obeyed in these adsorbent/metal ion systems. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3359–3363, 1997 相似文献
992.
β‐Cyclodextrin (β‐CD) derivatives 1 with an amino group at C(6), C(3), or C(2) were homogeneously linked together by an ethylenediaminetetraacetic acid (EDTA) bridge (Scheme). Coordination of the linker to metal ions and cooperation of the dual cavities of 3 in binding hydrophobic guests were properly demonstrated by NMR techniques and a fluorescence‐based titration method, respectively. The hydrolysis of bis(4‐nitrophenyl) phosphate (BNPP) in the presence of CeIV complexes of β‐CD dimers 3 was tens of millionfold faster than that in the absence of the CeIV complexes. Hydrophobic binding of the β‐CD cavities was estimated to contribute to the catalysis by a factor of up to 520, and the type of modified sugar unit and the bridging positions influenced this cooperation between the β‐CD moieties and the catalytic metal center. 相似文献
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994.
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996.
Tsuyoshi Akiyama Masato Nakada Kosuke Sugawa Sunao Yamada 《Macromolecular Symposia》2008,270(1):171-176
The effect of localized surface plasmon resonance (SPR) appearing at the surfaces of gold nanoparticles (AuPs) was successfully applied for the enhancement of photocurrents from porphyrin ( Po ) immobilized on AuPs. The electrode consisting of AuPs with different sizes (∼15 or ∼35 nm) was prepared using the AuP film formed at the liquid/liquid interface, and then Po was self-assembled on the gold surface. The SPR effect for the AuP film was verified from the attenuated total reflection SPR and absorption measurements. Photocurrents from the modified electrodes were compared with the corresponding planar electrode. Appreciable enhancement of photocurrents was observed. 相似文献
997.
Naoki Sato Shun-ichiro Ueno Emi Ohno Masato Tamura Yasuaki Ueki Ryo Yoshiie Ichiro Naruse 《Proceedings of the Combustion Institute》2019,37(3):2875-2882
In this study, the effects of mechanical stresses on the shedding of ash deposits in a coal-fired boiler were evaluated. We have confirmed that the shedding occurred because of the fracture within the initial deposit layer, which was formed by powdered ash residues. Therefore, assuming that the mechanical stress acting on the initial layer influenced the shedding, the distribution of the tensile stress and shear stresses acting on the initial deposit was calculated on the basis of elastic mechanism. Because the ash deposits were brittle in nature, it was assumed that the initial deposit failed on the basis of the maximum principal stress theory (MPST). The stress values were calculated based on the data for deposit shapes, which were obtained through previous ash deposition experiments on two bituminous coals, one subbituminous coal, and two lignite coals. The fracture strength of the deposit increased with a decrease in the ash fusion temperature. This result indicated that the strength of the deposit increased because of ash coalescence. Moreover, as the MPST, the starting point of fracture was estimated from the position where the principal stress became the largest, and the stress value was used to presume whether the fracture depended on tensile stress or shear stress. The deposit with a narrow adherence region failed because of tensile stress, and the signature of peeling due to tensile stress was observed in the cross-sectional scanning electron microscopy (SEM) image of the deposit after ash shedding. In contrast, the deposit with a wide adherence region failed because of shear stress. Therefore, peeling was not observed in the cross-sectional SEM image of the deposit after ash shedding. The results obtained from the analysis on the basis of the MPST well with the actual behavior of ash shedding. 相似文献
998.
Kyosuke Morimoto Thien Phuc Le Sudipta Kumar Manna I. N. Chaithanya Kiran Shinji Tanaka Masato Kitamura 《化学:亚洲杂志》2019,14(19):3283-3290
A ZnII complex of a C2‐chiral bisamidine‐type sp2N bidentate ligand ( L R ) possessing two dioxolane rings at both ends catalyzes a highly efficient quinone asymmetric Diels‐Alder reaction (qADA) between o‐alkoxy‐p‐benzoquinones and 1‐alkoxy‐1,3‐butadienes to construct highly functionalized chiral cis‐decalins, proceeding in up to a >99:1 enantiomer ratio with a high generality in the presence of H2O (H2O:ZnII=4–6:1). In the absence of water, little reaction occurs. The loading amount of the chiral ligand can be minimized to 0.02 mol % with a higher Zn/ L R ratio. This first success is ascribed to a supramolecular 3D arrangement of substrates, in which two protons of an “H2O‐ZnII” reactive species make a linear hydrogen bond network with a dioxolane oxygen atom and one‐point‐binding diene; the ZnII atom captures the electron‐accepting two‐points‐binding quinone fixed on the other dioxolane oxygen atom via an n‐π* attractive interaction. The mechanisms has been supported by 1H NMR study, kinetics, X‐ray crystallographic analyses of the related Zn L R complexes, and ligand and substrate structure‐reactivity‐selectivity relationship. 相似文献
999.
1000.