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51.
Vermoortele F Ameloot R Vimont A Serre C De Vos D 《Chemical communications (Cambridge, England)》2011,47(5):1521-1523
After controlled pretreatment, some Zr-terephthalate metal-organic frameworks are highly selective catalysts for the cross-aldol condensation between benzaldehyde and heptanal. The proximity of Lewis acid and base sites in the amino-functionalized UiO-66(NH(2)) material further raises the reaction yields. 相似文献
52.
Peeters A Valvekens P Vermoortele F Ameloot R Kirschhock C De Vos D 《Chemical communications (Cambridge, England)》2011,47(14):4114-4116
Double metal cyanides (DMCs) are highly active recyclable heterogeneous catalysts for hydroamination of phenylacetylene with 4-isopropylaniline. The best hydroamination yields are obtained with Zn-Co DMCs, especially if the particle size is decreased by a reverse emulsion synthesis technique. 相似文献
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Frederik Herzberg 《Mathematical Logic Quarterly》2008,54(6):666-667
?o?'s theorem for bounded D ‐ultrapowers, D being the ultrafilter introduced by Kanovei and Shelah [4], is established. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The partial differential equation associated with the system of difference-differential equations of Raman-Nath for the amplitudes of the diffracted light-waves is solved exactly by the method of the separation of the variables. The solution is presented as a double infinite series containing the Fourier coefficients of the even periodic Mathieu functions with periodπ and the corresponding eigenvalues. Considering this solution as a Laurent series in one of the variables, the Laurent coefficients immediately give the exact expressions for the amplitudes of the diffracted light-waves, from which the formulae for the intensities are calculated. The connection between the Raman-Nath method and Brillouin’s Mathieu function method has thus been achieved. 相似文献
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Johannes Maschita Dr. Tanmay Banerjee Gökcen Savasci Dr. Frederik Haase Prof. Christian Ochsenfeld Prof. Bettina V. Lotsch 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(36):15880-15888
Covalent organic frameworks (COFs) are an extensively studied class of porous materials, which distinguish themselves from other porous polymers in their crystallinity and high degree of modularity, enabling a wide range of applications. COFs are most commonly synthesized solvothermally, which is often a time-consuming process and restricted to well-soluble precursor molecules. Synthesis of polyimide-linked COFs (PI-COFs) is further complicated by the poor reversibility of the ring-closing reaction under solvothermal conditions. Herein, we report the ionothermal synthesis of crystalline and porous PI-COFs in zinc chloride and eutectic salt mixtures. This synthesis does not require soluble precursors and the reaction time is significantly reduced as compared to standard solvothermal synthesis methods. In addition to applying the synthesis to previously reported imide COFs, a new perylene-based COF was also synthesized, which could not be obtained by the classical solvothermal route. In situ high-temperature XRPD analysis hints to the formation of precursor–salt adducts as crystalline intermediates, which then react with each other to form the COF. 相似文献
60.
M. Sc. Frederik Kramm M. Sc. Johannes Teske M. Sc. Franziska Ullwer Wolfgang Frey Prof. Dr. Bernd Plietker 《Angewandte Chemie (International ed. in English)》2018,57(40):13335-13338
Cationic Fe complexes of the general type [(Ph3P)2Fe(CO)(NO)]X (X=BF4, BArF4) catalyze the redox‐neutral cycloisomerization of 1,6‐ and 1,7‐enyneacetates to afford bicyclic cyclobutanes under mild conditions in good yields and diastereoselectivities. 相似文献