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81.
R. Benedikt F. Ulzer Focke Finkener Th. Morawski Alfred H. Allen O. Schweissinger R. Marzahn Dieterich Hazura F. W. A. Woll Bruno Röse Ch. Dubois L. Padé R. Bensemann Audoynaud Levallois T. Leone A. Longi F. Benecke Joseph Herz P. Soltsien C. Schädler C. L. Reimer W. Will und H. Hager 《Fresenius' Journal of Analytical Chemistry》1888,27(1):524-539
Ohne Zusammenfassung 相似文献
82.
Ju-Nam Y Bricklebank N Allen DW Gardiner PH Light ME Hursthouse MB 《Organic & biomolecular chemistry》2006,4(23):4345-4351
We report the synthesis and structural characterisation of a new family of stable phosphonioalkylthiosulfate zwitterions, R3P+ (CH2)nS2O3- (R = Ph or Bu, n = 3,4,6, 8 or 10) which behave as cationic masked thiolate ligands with applications in the functionalisation of gold nanoparticles, having potential as new diagnostic biorecognition systems. The ligands were prepared by treatment of omega-bromoalkylphosphonium salts with sodium thiosulfate. The crystal and molecular structures of the zwitterions (R = Ph, n = 3) and (R = Bu, n = 3) were determined. A series of phosphonioalkanethiolate-capped gold nanoparticles dispersed in water was prepared by borohydride reduction of potassium tetrachloroaurate in the presence of the zwitterions in a dichloromethane-water system. UV-visible spectroscopy and scanning transmission electron-microscopy indicated that capped nanoparticles of ca. 5 nm diameter were present. 相似文献
83.
Andreas Braeuer Robert Fabian Hankel Markus Konstantin Mehnert Julian Jonathan Schuster Stefan Will 《Journal of Raman spectroscopy : JRS》2015,46(11):1145-1149
We report a Raman technique applicable for the in situ analysis of the development of hydrogen bonds in the liquid water‐rich phase just before the onset of gas hydrate formation. Herewith, the phase transition as well as the working principle of hydrate formation inhibitors and promoters can be analyzed. © 2015 The Authors. Journal of Raman Spectroscopy published by John Wiley & Sons Ltd. 相似文献
84.
Levason W Light ME Maheshwari S Reid G Zhang W 《Dalton transactions (Cambridge, England : 2003)》2011,40(19):5291-5297
The preparations and spectroscopic characterisation of the hydrolytically unstable As(III) complexes, [AsF(3)(OPR(3))(2)] (R = Me or Ph) and [AsF(3){Me(2)P(O)CH(2)P(O)Me(2)}] are described and represent the first examples of complexes of AsF(3) with neutral ligands. The crystal structure of [AsF(3){Me(2)P(O)CH(2)P(O)Me(2)}] contains dimers with bridging diphosphine dioxide, but there are also long contacts between the dimers to neighbouring phosphine oxide groups, completing a very distorted six-coordination at arsenic and producing a weakly associated polymer structure. The reaction of AsF(3) with OAsPh(3) affords Ph(3)AsF(2), and no arsine oxide complex was formed. Reaction of SbF(3) with OER(3) (R = Me or Ph, E = P or As), Me(2)P(O)CH(2)P(O)Me(2) and Ph(2)P(O)(CH(2))(n)P(O)Ph(2) (n = 1 or 2) in MeOH produces [SbF(3)(OER(3))(2)], [SbF(3){Me(2)P(O)CH(2)P(O)Me(2)}] and [SbF(3){Ph(2)P(O)(CH(2))(n)P(O)Ph(2)}] respectively. The X-ray structures reveal that the complexes contain square pyramidal SbF(3)O(2) cores with apical F and cis disposed pnictogen oxides. However, whilst [SbF(3)(OER(3))(2)] (R = Ph: E = P or As; R = Me: E = As) and [SbF(3){Ph(2)P(O)CH(2)P(O)Ph(2)}] are monomeric, [SbF(3){Me(2)P(O)CH(2)P(O)Me(2)}] is a dimer with bridging diphosphine dioxides producing a twelve-membered ring, and [SbF(3){Ph(2)P(O)(CH(2))(2)P(O)Ph(2)}] is a chain polymer with diphosphine dioxide bridges. In the OAsR(3) reactions with SbF(3), R(3)AsF(2) are also formed. Notably the Sb-O(P) bonds are shorter than As-O(P), despite the covalent radii (As < Sb), consistent with very weak coordination of the AsF(3). IR and multinuclear ((1)H, (19)F and (31)P) NMR data are reported and discussed. BiF(3) does not react with pnictogen oxide ligands under similar conditions and halide exchange of bismuth chloro complexes with Me(3)SnF gave BiF(3). 相似文献
85.
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88.
Simona Percec Ross Getty Will Marshall Gabriel Skidd Roger French 《Journal of polymer science. Part A, Polymer chemistry》2004,42(3):541-550
Oligomers consisting of aromatic building blocks separated by alkynyl units were synthesized by Sonogashira cross-coupling of aryl halides with terminal acetylenes. Strong electron acceptors such as F and CF3 and weak electron donors like CH3 were placed as substituents on one of the benzene rings. Acetyl-protected sulfhydryl groups were attached to one end of these molecules to promote their self-organization on gold surfaces. The electron-transport properties of such self-assembled monolayers (SAMs) are highly sensitive to the local order of the molecules in the solid state. Single crystals were analyzed by X-ray diffraction experiments that revealed structural details that could lead to a better understanding of the electron-transport properties. The unsymmetrical substitution of the aromatic rings by electron-active groups in the ortho-, meta-, or para positions resulted in changes of such molecular parameters as bonding and torsion angles and planarity. These parameters, in turn, can affect the angle of the molecular attachment to a gold substrate and the density of the resulting SAMs. Patterned SAMs of some of these molecules and comparison alkane thiols were obtained on gold by microcontact printing or flooding. The SAM thickness was determined by spectroscopic ellipsometry. Surface potential differences between adjacent SAMs or between SAMs and the gold substrate were measured by scanning surface potential microscopy under ambient conditions. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 541–550, 2004 相似文献
89.
Novel Oxygen Storage Components Promoted Palladium Catalysts for Emission Control in Natural Gas Powered Engines 总被引:1,自引:0,他引:1
BinZHAO MaoChuGONG XueSongFENG YongYueLUO 《中国化学快报》2005,16(1):97-99
A three-way catalyst comprised novel oxygen storage components for emission control in natural gas powered engines was prepared. The addition of novel oxygen storage components to the Pd/γ-Al2O3 catalysts resulted in improved activities of the fresh and aged catalyst by lowering the light-off temperature for methane in natural gas engines exhaust. 相似文献
90.
Joykrishna Dey A. Yvette Will Rezik A. Agbaria Peter W. Rabideau Atteye H. Abdourazak Renata Sygula Isiah M. Warner 《Journal of fluorescence》1997,7(3):231-236
The spectroscopic properties of corannulene and cyclopentacorannulene are examined by use of absorption and steady-state fluorescence
measurements. A red shift in the emission maxima of cyclopentacorannulene is noted with respect to the emission maxima in
the corannulene spectrum. Similar differences in the absorption spectra of both molecules are also observed. Reasons for the
dissimilarities in the absorption and emission spectra of these molecules are discussed. The fluorescence quantum yields and
lifetimes of the molecules measured in organic solvents are reported. The fluorescence quantum yield and lifetime of cyclopentacorannulene
are lower than those of corannulene. This difference is attributed to the highly strained and nonplanar structure of cyclopentacorannulene.
The effectiveness of nitromethane as a quencher of corannulene and cyclopentacorannulene fluorescence is examined. In contrast
to previously reported results, the fluorescence of these molecules is quenched by nitromethane. Fluorescence quenching of
the molecules has been attributed to complex formation in the ground state, i.e., static quenching. 相似文献