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991.
Daisuke BabaToshio Fuchigami 《Tetrahedron letters》2003,44(15):3133-3136
Anodic oxidation of cyclic imidates, 2-aryl-2-oxazolines, in methanol provided the corresponding 4-methoxylated products. Anodic α-methoxylation and α-acetoxylation of open-chain imines derived from glycine esters and benzophenone were also achieved using a bromide ion mediator. On the other hand, anodic α-acetoxylation of CF3-containing imine and imidate was successful without use of the bromine mediator. This is the first example of successful anodic α-substitution of imines and imidates. 相似文献
992.
Inoue S Uchihashi T Yamamoto D Ando T 《Chemical communications (Cambridge, England)》2011,47(17):4974-4976
The processes of dynamic aggregate transformations of micelles at a mica surface were observed using high-speed atomic force microscopy. We showed that salt concentration affects not only the equilibrium state adsorbed structure but also the time required to reach the equilibrium state on the mica surface. 相似文献
993.
Takahashi D Hirono S Toshima K 《Chemical communications (Cambridge, England)》2011,47(42):11712-11714
A fullerene derivative was found to be capable of photodegrading oligosaccharides under irradiation with not only UV but also visible light. Furthermore, target-selective photodegradation of oligosaccharides (β-D-galactofuranosides) was achieved by a designed and synthesized fullerene-boronic acid hybrid upon irradiation with visible light in the absence of any additives under neutral conditions. 相似文献
994.
Miyauchi Y Kourist R Uemura D Miyamoto K 《Chemical communications (Cambridge, England)》2011,47(26):7503-7505
Using three rounds of structure-guided directed evolution, the catalytic activity of the (S)-selective arylmalonate decarboxylase variant G74C/C188S could be increased up to 920-fold. The best variant had a 220-fold improved activity in the production of (S)-naproxen with excellent enantioselectivity (>99% ee). 相似文献
995.
Kazuhide Ichikawa Ayumu Wagatsuma Yusaku I. Kurokawa Shigeyoshi Sakaki Akitomo Tachibana 《Theoretical chemistry accounts》2011,130(2-3):237-250
We study the electronic structure of two types of transition metal complexes, the inverted-sandwich-type and open-lantern-type, by the electronic stress tensor. In particular, the bond order $b_\varepsilon$ measured by the energy density which is defined from the electronic stress tensor is studied and compared with the conventional MO-based bond order. We also examine the patterns found in the largest eigenvalue of the stress tensor and corresponding eigenvector field, the ??spindle structure?? and ??pseudo-spindle structure??. As for the inverted-sandwich-type complex, our bond order $b_\varepsilon$ calculation shows that relative strength of the metal-benzene bond among V, Cr, and Mn complexes is V?>?Cr?>?Mn, which is consistent with the MO-based bond order. As for the open-lantern-type complex, we find that our energy density-based bond order can properly describe the relative strength of Cr?CCr and Mo?CMo bonds by the surface integration of the energy density over the ??Lagrange surface?? which can take into account the spatial extent of the orbitals. 相似文献
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1000.
Nakazawa S Sato K Shiomi D Yano M Kinoshita T Franco ML Lazana MC Shohoji MC Itoh K Takui T 《Physical chemistry chemical physics : PCCP》2011,13(4):1424-1433
Trianionic spin-quartet and tetraanionic spin-quintet molecular clusters derived from m-dibenzoylbenzene in solution were identified by CW-ESR/pulse-ESR based two-dimensional electron spin transient nutation spectroscopy, and their spin and clustering structures in the ground state were determined in terms of a D-tensor based phenomenological approach and DFT calculations. The molecular structures obtained semiempirically are supported by DFT-based quantum chemical calculations. The DFT calculations have been tested for a sodium ion bridged fluorenone-based cluster, [fluorenone(-)˙ {Na(+)(dme)(2)}](2), whose crystal structure was reported in the literature [H. Bock, H.-F. Herrmann, D. Fenske and H. Goesmann, Angew. Chem., Int. Ed. Engl., 1988, 27, 1067], reproducing the experimentally determined moelcular structure of the dimer cluster. It is suggested that both the quartet and quintet clusters in the 2-MTHF glass and solution form the cross-typed structures with the two m-dibenzoylbenzene moieties in cis-configuration. A dianionic spin-triplet m-dibenzoylbenzene derivative was detected for the first time and its charge and spin densities were studied by the quantum chemical calculations. The high-spin states of the open-shell entities under study were confirmed by X-band pulse-ESR based electron spin nutation spectroscopy in organic frozen glasses. The D values and other spin Hamiltonian parameters of all the polyanionic high-spin species were determined by the hybrid eigenfield spectral simulation for fine-structure ESR spectra. m-Dibenzoylbenzene provides pseudo-degenerate π-LUMOs arising from its topological symmetry of the π-electron network and its dianion in the triplet ground state is a prototypical model for topologically-controlled genuinely organic ferromagnetic metals. 相似文献