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141.
Joy Chakraborty Brajagopal Samanta Guillaume Pilet Samiran Mitra 《Structural chemistry》2006,17(6):585-593
A new hydrogen-bonded polymeric Mn(III) complex C19H20Mn1N3O3S1 (1) has been synthesised by conventional procedure with a new Schiff base ligand (2Z,3Z)-N
1,N
2-bis(1-(2-hydroxyphenyl)ethylidene)ethane-1,2-diamine (H
2
L) bearing a tetradentate N2O2 donor site. The complex has been characterised with several spectroscopic techniques like FT-IR, UV/Vis and EPR and also
well supported by variable temperature magnetic susceptibility study. The structure of the co-ordination complex has been
unequivocally confirmed from single crystal X-ray diffraction study. The redox stability of the metal chelate complex has
been investigated with a slow scan cyclic voltammetry. 相似文献
142.
Optical absorption and fluorescence behaviour of two rigorously purified imidazolium ionic liquids, 1-butyl-3-methylimidazolium
bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazoliumbis(trifluoromethanesulfonyl)imide are studied in the neat condition and in solution. Non-negligible absorption in the UV region
with a long tail extending into the visible region is the main feature of the absorption. Excitation wavelength-dependent
two-component fluorescence characterizes the emission behaviour of these liquids. That ion association gives rise to the long
absorption tail and shifting fluorescence maximum, which appears to be common to most of the imidazolium ionic liquids, is
evident from the effect of the conventional solvents 相似文献
143.
V. Raj Gopal V. Jayathirtha Rao G. Saroja A. Samanta 《Chemical physics letters》1997,270(5-6):593-598
The fluorescence properties of some pyrenylethylene derivatives capable of exhibiting twisted intramolecular charge transfer phenomenon havebeen studied as a function of solvent polarity. The solvent polarity dependent change in the fluorescence quantum yield has been interpreted in terms of intramolecular retational relaxations. The trans → cis photoisomerization data of the compounds indicate that the twist around the ethylenic double bond is accelerated in polar solvents. 相似文献
144.
Chhanda Samanta 《Acta Physica Hungarica A》2004,19(1-2):161-162
This mass formula explains gross features of the binding energy curves for all the elements from Li to Bi. It has no shell effects incorporated. Comparisons of separation energies computed from this formula and measured masses show extra-stability at N=6 (Z=3?8), Z=6 (N=6?9), N=14 (Z=7?10), Z=14 (N=14?19), N=16 (Z=7?8), Z=16 (N=24?26), loss of magicity at N=8 (Z=4), N=20 (Z=12?15) and quenching of N=50, 82, 126, Z=50 near driplines. Z=82 magicity rises at N=104 after strong quenching near N=107. 相似文献
145.
The synthesis of highly substituted dibenzo-azocine systems is still lacking. An efficient synthetic protocol utilizing the sequential aromatic aza-Claisen rearrangement followed by the implementation of the intramolecular Heck reaction as a key step has been developed for the synthesis of various dibenzo-azocine derivatives of biological relevance. 相似文献
146.
The synthesis and single crystal structure of 25,27-(diamidomonoazacrown-5)-calix[4]arene (L), calix[4]arene capped by a diamide bridge in the 1,3-position on the lower rim, which forms a supramolecular dimer in the solid state via intermolecular hydrogen bonding, are described. A 4-aminophthalimide (AP) fluorophore has been regioselectively linked to the secondary amino function of the azacrown unit with a dimethylene spacer to construct N-(4-aminophthalimidoethyl)calix[4]azacrown (APL), a fluorescent sensor, via a fluorophore-spacer-receptor architecture. Fluorescence quantum yield and lifetime of APL have been measured to be lower than those of the bare fluorophore (AP) due to the photoinduced intramolecular electron transfer (PIET) between the fluorophore and the receptor moieties of the molecule. In the presence of transition metal ions, fluorescence enhancement of is observed suggesting the binding of the metal ion to the sensor. Complexation properties of APL with transition metal ions are investigated using UV-vis spectroscopy. A 1 : 1 stoichiometry of the complex is determined from a Job plot and the corresponding association constants for the various metal ions are evaluated. Fe(3+) and Cu(2+) ions have the largest association constants (K= 2.3 x 10(5) M(-1) and 1.6 x 10(5) M(-1) respectively) compared to other metal ions indicating that they form complexes selectively with APL. 相似文献
147.
A. Gupta S.B. Samanta V.P.S. Awana H. Kishan A.M. Awasthi S. Bhardwaj A.V. Narlikar C. Frontera J.L. Garcia-Munoz 《Physica B: Condensed Matter》2005,370(1-4):172-177
We present a study of charge ordering and electronic phase separation (EPS) phenomenon in BixSr1−xMnO3, for an exhaustive range of x (0.25x0.75), by STM/STS at room temperature (RT) and specific heat measurements at high temperatures (350–650 K). Atomically resolved STM images of the samples, in real space, show the presence of stripe-like charge-ordered (CO) phase coexisting with charge-disordered (CD) phase. The STM images further reveal that the fraction of CO phase increases with an increase in x. The conductance spectra of these phases measured at nano level by STS are discussed. The transition to CO phase above RT is corroborated by specific heat measurements in all samples, giving a TCO(x) phase diagram for this system. 相似文献
148.
A calculation is performed using lowest order Brueckner theory in momentum space, with explicit isobar configurations included through the coupled channel mathod. The effective interaction for the1 S 0-5 D 0 channel is extracted from this calculation. Two different transition potentials are used — one due to Green and Niskanen (1976), the other, due to Green and co-workers (1978). The nucleon-nucleon (NN) interaction used is the Reid soft core potential, compensated for the inclusion of the explicit isobar channel. The effective interaction shows marked momentum dependence in the intermediate range. The loss of attraction depends on the transition potential one chooses. The correlation function involving the nucleon-isobar intermediate state is anti-correlated to the NN part. 相似文献
149.
M. Samanta 《Annals of the Institute of Statistical Mathematics》1965,17(1):363-375
Conclusion The results obtained in this note are subject to many limitations. We have considered a very simple rule of subdivision of
a bivariate population. It is quite natural to think that there may exist other rules of stratification leading to a considerable
decrease of the standard error of the estimates. In practical situations the stratification variables are generally different
from the estimation variables. Moreover by considering a hypothetical population it has been possible to neglect the finite
population correction. The utility of the result is also handicapped due to computational difficulties. 相似文献
150.
Shukla AD Ganguly B Dave PC Samanta A Das A 《Chemical communications (Cambridge, England)》2002,(22):2648-2649
Newly synthesised Ru(bp)2(sq)(+)-derivatives, covalently linked to a porphyrin-core, show very high epsilon values in the NIR region; which exhibit fast on/off switching depending on the redox state of the coordinated dioxolene functionality. 相似文献