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1.
2.
A study of the preparations of the complex hydridic anions [MH(6)](4)(-) (M = Fe and Ru) reveals a number of distinctive features. Here a soluble homoleptic ruthenium hydride has been prepared for the first time. For example, both FeX(2) and [Ru(eta(4)-1,5-COD)X(2)], X = Cl and Br, react with PhMgBr solutions under hydrogen to produce the title compounds. The benzene liberated in these reactions is more readily hydrogenated in the case of a homogeneous room temperature ruthenium hydride preparation to both cyclohexane and cyclohexene. The (1)H NMR spectroscopic data show that the two complex anions have hydride absorptions in the low-frequency region, delta -20.3 and -14.7, respectively. Further, (1)H spin-lattice relaxation times (T(1)) for M-H are longer in the case of Ru vs Fe. 相似文献
3.
John F. Callan A. P. De Silva R. C. Mulrooney B. Mc Caughan 《Journal of inclusion phenomena and macrocyclic chemistry》2007,58(3-4):257-262
Summary This review highlights recent advances in the use of quantum dots (QD’s) as luminescent sensors. The bulk of the study concentrates
on systems that possess organic ligands bound to the surface of QD’s. These ligands vary from low molecular weight thiols
to larger molecules such as maltose binding protein. All have one thing in common: when a target analyte binds to the ligand/receptor,
a perturbation of the system occurs, that registers itself as a change in the luminescence intensity of the QD. Two main mechanisms
are prevalent in controlling the luminescent intensity in such systems. The first is Photoinduced Electron Transfer (PET)
and the second energy transfer. This review looks at current sensors that operate by using these mechanisms. Two component
systems are also investigated where a quencher is first added to a solution of the QD, followed by addition of the target
analyte that interacts with the quencher to influence the luminescence intensity. 相似文献
4.
M. A. Khakoo J. W. Mc Conkey 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1986,3(1):69-72
Electron-polarised photon coincidence techniques are used to determine linear and circular polarisation correlations from the differential electron impact excitation of the 21 P state of helium at an incident electron energy of 140 eV. At 30° and 45° electron scattering angles, all the Stokes parameters are determined, whereas at 52.5° onlyP 2 is measured. Comparisons are made with the distorted wave (DW) calculations of Madison [11] and the first order many-body theory (FOMBT) of Cartwright and Csanak [4]. 相似文献
5.
A chemical inhibitor reveals the role of Raf kinase inhibitor protein in cell migration 总被引:7,自引:0,他引:7
Raf kinase inhibitor protein (RKIP) is a modulator of cell signaling that functions as an endogenous inhibitor of multiple kinases. We demonstrate here a positive role for RKIP in the regulation of cell locomotion. We discovered that RKIP is the relevant cellular target of locostatin, a cell migration inhibitor. Locostatin abrogates RKIP's ability to bind and inhibit Raf-1 kinase, and it acts by disrupting a protein-protein interaction, an uncommon mode of action for a small molecule. Small interfering RNA-mediated silencing of RKIP expression also reduces cell migration rate. Overexpression of RKIP converts epithelial cells to a highly migratory fibroblast-like phenotype, with dramatic reduction in the sensitivity of cells to locostatin. RKIP is therefore the compound's valid target and a key regulator of cell motility. 相似文献
6.
7.
Synthetic organic chemists are continually looking for milder, more specific methods of effecting given transformations, and one such problem which recently arose in our laboratory involved ester cleavage. In particular, we sought a specific, wild, non-hydrolytic method for effecting teh ester - acid transformation under conditions which other acid or base sensitive functional groups would survive. 相似文献
8.
Motivated by a recent paper of Liu and Ma, we describe a number of general WP-Bailey chains. We show that many of the existing
WP-Bailey chains (or branches of the WP-Bailey tree), including chains found by Andrews, Warnaar and Liu and Ma, arise as
special cases of these general WP-Bailey chains. We exhibit three new branches of the WP-Bailey tree, branches which also
follow as special cases of these general WP-Bailey chains. Finally, we describe a number of new transformation formulae for
basic hypergeometric series which arise as consequences of these new WP-Bailey chains. 相似文献
9.
S.?Aumaítre J.?Farago S.?FauveEmail author S.?Mc?Namara 《The European Physical Journal B - Condensed Matter and Complex Systems》2004,42(2):255-261
Using two-dimensional numerical simulations of a granular gas excited by vibrating one of the container boundaries, we study the fluctuations of its total kinetic energy, of the power injected into the gas by the moving boundary and of the power dissipated by inelastic collisions. We show that an effective number N
f
of degrees of freedom that depends on the inelasticity of collisions can be extracted from the probability density function (PDF) of the fluctuations of the total kinetic energy E.
is then an intensive variable contrary to the usually defined granular temperature
. We then show that an intensive temperature can also be calculated from the probability of certain large deviations of the injected power. Finally, we show that the fluctuations of injected and dissipated power are related such that their ratio is inversely proportional to the square-root of the ratio of their correlation times. This allows to define a quantity homogenous to a temperature that is intensive and conserved in the process of energy dynamics from its injection by the driving piston to its dissipation by inelastic collisions.Received: 3 August 2004, Published online: 14 December 2004PACS:
05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion - 05.45.-a Nonlinear dynamics and nonlinear dynamical systems 相似文献
10.