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排序方式: 共有177条查询结果,搜索用时 15 毫秒
91.
Kovacs-Nagy R Sarkozy P Hu J Guttman A Sasvari-Szekely M Ronai Z 《Electrophoresis》2011,32(15):2013-2020
Synaptosomal-associated protein 25 (SNAP-25) plays a crucial role in exocitosis. Single nucleotide polymorphisms (rs3746544 and rs1051312) in the 3' un-translated region of the SNAP-25 gene have been described to be in association with attention-deficit hyperactivity disorder. As the disease affects millions of children world-wide, understanding the genetic background of attention-deficit hyperactivity disorder is of crucial importance. Efficient and reliable PCR-RFLP protocols were elaborated for the genotyping of the rs3746544 and rs1051312 SNPs employing a high-throughput capillary electrophoresis method for fragment analysis. A novel real-time PCR-based technique was used applying sequence specific TaqMan probes to haplotype the two SNPs, and the G-C haplotype could not be detected in a large Caucasian population (N=1376). These findings have been confirmed by molecular biology tools as well as by the PHASE Bayesian computational approach. In silico analyses have suggested that the two SNPs might alter microRNA binding and thus have an effect on SNAP-25 production. We have demonstrated that this biological information can be revealed only by direct haplotype analysis emphasizing the importance of our novel molecular haplotye analysis protocol. Results of the study of the two SNPs might shed light on the association of SNAP-25 variants and pathological phenotypes at the molecular level. 相似文献
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93.
Thomas Schramm Gerd Ganteför Andras Bodi Partick Hemberger Thomas Gerber Bernd von Issendorff 《Applied Physics A: Materials Science & Processing》2014,115(3):771-779
A new experimental setup for photoelectron spectroscopy of size-selected cluster ions using synchrotron VUV radiation as generated by the Swiss Light Source is presented. An intense positively charged cluster ion beam is produced in a high-intensity magnetron sputter source. The clusters are subsequently mass selected in a sector magnet. To maximize the residence time of the cluster ions in the ionization region of the velocity map imaging spectrometer, the cluster ion beam is decelerated where it crosses the light beam. First experiments on (MoO3) n + (n = 69 and 59) cluster cations show that the approach is capable of delivering photoelectron spectra of size-selected transition metal cluster ions. 相似文献
94.
Katharina Majer Prof. Ruth Signorell Dr. Maarten F. Heringa Maximilian Goldmann Dr. Patrick Hemberger Dr. Andras Bodi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(62):14192-14204
The photoionization of thymine has been studied by using vacuum ultraviolet radiation and imaging photoelectron photoion coincidence spectroscopy after aerosol flash vaporization and bulk evaporation. The two evaporation techniques have been evaluated by comparison of the photoelectron spectra and breakdown diagrams. The adiabatic ionization energies for the first four electronic states were determined to be 8.922±0.008, 9.851±0.008, 10.30±0.02, and 10.82±0.01 eV. Vibrational features have been assigned for the first three electronic states with the help of Franck–Condon factor calculations based on density functional theory and wave function theory vibrational analysis within the harmonic approximation. The breakdown diagram of thymine, as supported by composite method ab initio calculations, suggests that the main fragment ions are formed in sequential HNCO-, CO-, and H-loss dissociation steps from the thymine parent ion, with the first step corresponding to a retro-Diels–Alder reaction. The dissociation rate constants were extracted from the photoion time-of-flight distributions and used together with the breakdown curves to construct a statistical model to determine 0 K appearance energies of 11.15±0.16 and 11.95±0.09 eV for the m/z 83 and 55 fragment ions, respectively. These results have allowed us to revise previously proposed fragmentation mechanisms and to propose a model for the final, nonstatistical H-loss step in the breakdown diagram, yielding the m/z 54 fragment ion at an appearance energy of 13.24 eV. 相似文献
95.
Guido Zichittella Matthias Scharfe Begoa Purtolas Vladimir Paunovi Patrick Hemberger Andras Bodi Lszl Szentmiklsi Núria Lpez Javier Prez‐Ramírez 《Angewandte Chemie (International ed. in English)》2019,58(18):5877-5881
The product distribution in direct alkane functionalization by oxyhalogenation strongly depends on the halogen of choice. We demonstrate that the superior selectivity to olefins over an iron phosphate catalyst in oxychlorination is the consequence of a surface‐confined reaction. By contrast, in oxybromination alkane activation follows a gas‐phase radical‐chain mechanism and yields a mixture of alkyl bromide, cracking, and combustion products. Surface‐coverage analysis of the catalyst and identification of gas‐phase radicals in operando mode are correlated to the catalytic performance by a multi‐technique approach, which combines kinetic studies with advanced characterization techniques such as prompt‐gamma activation analysis and photoelectron photoion coincidence spectroscopy. Rationalization of gas‐phase and surface contributions by density functional theory reveals that the molecular level effects of chlorine are pivotal in determining the stark selectivity differences. These results provide strategies for unraveling detailed mechanisms within complex reaction networks. 相似文献
96.
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98.
Marton A Clark CC Srinivasan R Freundlich RE Narducci Sarjeant AA Meyer GJ 《Inorganic chemistry》2006,45(1):362-369
The metal-to-ligand charge-transfer (MLCT) excited states of Ru(bpy)(2)(deeb)(PF(6))(2), where bpy is 2,2-bipyridine and deeb is 4,4'-(CO(2)CH(2)CH(3))(2)-2,2'-bipyridine, in dichloromethane were found to be efficiently quenched by iodide at room temperature. The ionic strength dependence of the UV-visible absorption spectra gave evidence for ion pairing. Iodide was found to quench the excited states by static and dynamic mechanisms. Stern-Volmer and Benesi-Hildebrand analysis of the spectral data provided a self-consistent estimate of the iodide-Ru(bpy)(2)(deeb)(2+) adduct in dichloromethane, K = 59 700 M(-1). Transient absorption studies clearly demonstrated an electron-transfer quenching mechanism with transient formation of I(2)(*)(-) in high yield, phi = 0.25 for 355 or 532 nm excitation. For Ru(bpy)(2)(deeb)(PF(6))(2) in acetonitrile, similar behavior could be observed at higher iodide concentrations than that required in dichloromethane. The parent Ru(bpy)(3)(2+) compound also ion pairs with iodide in CH(2)Cl(2), and light excitation gave a higher I(2)(*)(-) yield, phi = 0.50. X-ray crystallographic, IR, and Raman data gave evidence for interactions between iodide and the coordinated deeb ligand in the solid state. 相似文献
99.
Sergei Gusev Stefan Johansson Bo Kågström Anton Shiriaev Andras Varga 《BIT Numerical Mathematics》2010,50(2):301-329
Efficient and accurate structure exploiting numerical methods for solving the periodic Riccati differential equation (PRDE)
are addressed. Such methods are essential, for example, to design periodic feedback controllers for periodic control systems.
Three recently proposed methods for solving the PRDE are presented and evaluated on challenging periodic linear artificial
systems with known solutions and applied to the stabilization of periodic motions of mechanical systems. The first two methods
are of the type multiple shooting and rely on computing the stable invariant subspace of an associated Hamiltonian system.
The stable subspace is determined using either algorithms for computing an ordered periodic real Schur form of a cyclic matrix
sequence, or a recently proposed method which implicitly constructs a stable deflating subspace from an associated lifted
pencil. The third method reformulates the PRDE as a convex optimization problem where the stabilizing solution is approximated
by its truncated Fourier series. As known, this reformulation leads to a semidefinite programming problem with linear matrix
inequality constraints admitting an effective numerical realization. The numerical evaluation of the PRDE methods, with focus
on the number of states (n) and the length of the period (T) of the periodic systems considered, includes both quantitative and qualitative results. 相似文献
100.
A Banach Space Whose Operator Algebra has K0-Group Q 总被引:4,自引:0,他引:4
We construct a Banach space X whose algebra of bounded linearoperators has K0-group the additive group of rational numbers.We achieve this using a Gowers-Maurey space. 2000 Mathematical Subject Classification: 20F36, 55P35, 55Q05,55Q40, 55U10 相似文献