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排序方式: 共有461条查询结果,搜索用时 15 毫秒
101.
Ashok Kumar Ashoke Chandra Deb S. K. Mukerjee V. N. Vaidya D. D. Sood 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):375-377
Solvent extraction of plutonium(VI) from nitric acid (1 to 5M) into 20% and 30% TBP in dodecane saturated with uranium(VI)
(0% to 80%) has been studied. For a particular nitric acid concentration, the distribution coefficient (K
d
) is found to decrease with the increase in saturation of organic phase with uranium(VI). At a fixed organic phase the saturationK
d
increased with increase in nitric acid concentration, however, the magnitude of this increase inK
d
decreased with the increase in saturation. 相似文献
102.
A wide variety of 3-aminocoumarins have been synthesized in large scale from the corresponding 3-acetamidocoumarins by regioselective cleavage of carbon–nitrogen bond using 70% sulfuric acid under reflux conditions. The synthesized 3-aminocoumarins were further brominated regioselectively at the 4-position of 3-aminocoumarin using BDMS as brominating agent. 相似文献
103.
Dr. Domenik Schleier Marius Gerlach Dr. Deb Pratim Mukhopadhyay Emil Karaev Dorothee Schaffner Dr. Patrick Hemberger Prof. Ingo Fischer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(42):e202201378
We have investigated the photoionization of ammonia borane (AB) and determined adiabatic ionization energy to be 9.26±0.03 eV for the X+ 2E←X 1A1 transition. Although the threshold photoelectron spectrum appears at first glance to be similar to the one of the isosteric ethane, the electronic situation differs markedly, due to different orbital energies. In addition, an appearance energy AE0K(NH3BH3, NH3BH2+)= 10.00±0.03 eV has been determined, corresponding to the loss of a hydrogen atom at the BH3-site. From the data, a 0 K bond dissociation energy for the B−H bond in the cation of 71.5±3 kJ mol−1 was derived, whereas the one in the neutral compound has been estimated to be 419±10 kJ mol−1. 相似文献
104.
We consider a system of Brownian particles confined in a two-dimensional bilobal enclosure. Varying cross-section of the confinement results in an effective entropic potential in reduced dimension. We show that the system may undergo an entropic noise-induced transition when the shape of the stationary probability density changes qualitatively from bimodal to trimodal type under the influence of a multiplicative noise. 相似文献
105.
[reaction: see text] A tin(II) chloride-mediated short, efficient, and practical regioselective synthesis of biheterocyclic 5,6-dihydro-quinazolino[4,3-b]quinazolin-8-ones with three-point diversity is reported. A one-step reductive transformation of 2-(2-nitrophenyl)-3H-quinazolin-4-one in various alcohols furnished the desired tetracyclic product in good yields with high purity. 相似文献
106.
Mean first passage time of a periodically driven particle for its escape over a fluctuating barrier with wells remaining unbiased exhibits a resonance when the frequency of the driving field is varied. This parametric variant of resonant activation and associated features of noise induced transition are realized in terms of a two-state model to estimate analytically several quantifiers of the escape event. Numerical simulation on a continuous double-well model collaborates our theoretical analysis. 相似文献
107.
Santanu Deb‐Choudhury Jeffrey E. Plowman Ancy Thomas Gail L. Krsinic Jolon M. Dyer Stefan Clerens 《Electrophoresis》2010,31(17):2894-2902
Identification of the intermediate filament proteins (IFPs) in the wool proteome has formerly been hampered by limited sequence information, the high degree of IFP homology and their close proximity on 2‐DE maps. This has been partially rectified by the recent acquisition of four new Type I and two Type II wool IFP sequences. Among closely migrating proteins, such as IFP clusters in a 2‐DE map, proteins with higher sequence coverage will be assigned higher scores, but the identification of unique peptides in such tight clusters may distinguish these closely migrating proteins. Two approaches were adopted for the study of wool IFPs. In the first, searches were conducted for peptides known to be unique to each member of the family in each spot. In the second, MALDI imaging was employed to examine peptides bound to a PVDF membrane from a poorly resolved part of the Type I IFP region of the 2‐DE map. As a result, a distinct picture has emerged of the distribution of the six Type I and four Type II IFPs across the 2‐DE wool protein map. 相似文献
108.
Expressions for the energies of the highest occupied π-molecular orbitals of a series of aromatic amines have been derived in terms of the vertex weight h N (for amine nitrogen) and edge weight k C–N (for the C–N bond) by representing the amine molecule in terms of vertex- and edge-weighted graphs. Graph-theoretical methods have been used to evaluate the quantities involved in such expressions. The HOMO energies of the amines calculated by density functional theory using the 6-31++G** basis set have been correlated with these expressions to estimate the perturbational parameter h N and the Coulomb integral α. The acceptability of the estimated values of α and h N has been tested by their ability to explain the experimentally observed trends in the CT transition energies of a series of charge-transfer complexes of amines with tetracyanoethylene. An important structural feature, namely rotation of the –NH2 group about the C–N bond due to steric repulsion with the nearest H-atom in the case of 1-amino compounds, has been observed by such a correlation. The result agrees well with the DFT-optimized geometries of the structures. 相似文献
109.
Deb Shankar Roy Kankan Bhattacharyya Subhas C. Bera Mihir Chowdhury 《Chemical physics letters》1980,69(1):134-140
A time-resolved study of the emission from benzil and naphthyl in semi-solid glasses (e.g. alcoholic glass near the melting point) using a pulsed N2-laser as an excitation source is reported. The emission from the relaxed excited triplet shows a growth followed by a decay. This growth provides a convincing proof of geometrical relaxation occurring in the excited states of benzil and naphthyl. 相似文献
110.
N. Deb 《Journal of Thermal Analysis and Calorimetry》2005,81(1):61-65
Summary A mixed metal oxalate, manganese(II)bis(oxalato)nickelate(II)tetrahydrate, has been synthesized and characterized by elemental analysis, IR spectral and X-ray powder diffraction (XRD) studies. Thermal decomposition studies (TG, DTG and DTA) in air showed that the compound decomposed mainly to Mn2O3, MnO2 and NiO at ca.1000°C, via. the formation of several intermediates. DSC study in nitrogen upto 500°C showed the endothermic decomposition. The tentative mechanism for the thermal decomposition in air is proposed. 相似文献