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41.
The present review deals with coherent states, its application to various problems in physics, chemistry and biology and its important applications to anharmonic, time-dependent and damped oscillator systems. It is seen that use of these states overcomes certain theoretical difficulties. 相似文献
42.
Trabecular bone with its porous structure is an important compressive load bearing member. Different structural factors such
as porosity, non-homogeneous deformation, varying trabeculae thickness, connectivity, and nanoscale (10 nm to 1 μm) to macroscale
(~0.1 mm to 10 mm) composition hierarchy determine the failure properties of trabecular bone. While the above factors have
important bearing on bone properties, an understanding of how the local nanoscale properties change at different macroscale
compressive strain levels can be important to develop an understanding of how bone fails. In the present work, such analyses
are performed on bovine femoral trabecular bone samples derived from a single animal. Analyses focus on measuring nanoindentation
elastic moduli at three distinct levels of compressive strains in the bone samples: (1) when the samples are not loaded; (2)
after the samples have been loaded to a strain level just before apparent yielding and the macroscale compression test is
stopped; and (3) after the samples have been compressed to a strain level after apparent yielding and the macroscale compression
test is stopped. Nanoindentation elastic modulus values are two orders of magnitude higher than the macroscale compressive
elastic modulus values of all samples. A high variability in macroscale compressive elastic modulus values is observed because
of porous architecture and small sample size. Nanoindentation elastic modulus values show a progressive reduction with increase
in the extent of macroscale compressive deformation. Apparent yielding has a significant effect on this trend. The decrease
in nanoindentation modulus value for all samples accelerates from approximately 20% before yielding to approximately 60% after
yielding in comparison to the nanoindentation modulus values at 0% strain level. The level of variation in the predicted nanoindentation
modulus values is the lowest for uncompressed samples (~16–18%). However, with increase in the extent of compression, the
level of variation increases. It varied between 50% and 90% for the samples tested after yielding showing a widespread heterogeneity
in local nanoscale structural order after apparent yielding. Scanning electron microscope (SEM) observations suggest that
apparent yielding significantly destroys local nanoscale structural order. However, quantitative results suggest that a significant
residual nanoscale stiffness varying from 5 GPa to 8 GPa among different samples still remains for possible repair facilitation. 相似文献
43.
R. Khare P.K. Shukla G.K. Mishra C. Mukherjee S. Talwar V.K. Dubey P. Saxena J.K. Mittal 《Optics Communications》2009,282(19):3850-3853
We present an analytical and experimental study of a novel confocal optical pulse stretcher (COPS). The simple and passive pulse stretcher consists of two concave mirrors and a scraper beam-splitter and its optical configuration ensures a perfect spatial overlapping of laser pulses at the beam-splitter. The pulse stretcher is compact and suitable for laser pulses of large divergences. The confocal optical pulse stretcher is demonstrated on a pulsed copper vapour laser to convert a 40 ns (1/e2 % points) pulse into a 55 ns with reduction of peak power by a factor of 1.375 without loss of pulse energy. 相似文献
44.
In this paper we explore the relation between information patterns and Nash Equilibria in extensive games. By information we mean what players know about moves made by others, as well as by chance. For the most part we confine ourselves to pure strategies. But in Section 2 behavioral strategies are also examined. It turns out that they can be modeled as pure strategies of an appropriately enlarged game. Our results, applied to the enlarged game, can then be reinterpreted in terms of the behavioral strategies of the original game. 相似文献
45.
46.
47.
K.S. Dubey 《Solid State Communications》1978,25(5):319-321
It is found that at low temperatures, the Callaway expression for the lattice thermal conductivity of a sample having dislocations reduces to the expression obtained by Dubey based on the nonlinear heat transfer theory. The obtained expression is used to explain the measurements of Wolfimeyer and Dillinger of phonon conductivity of sapphire in the temperature range 0.4–4 K. 相似文献
48.
Anuradha?MishraEmail author Rajani?Srinivasan Malvika?Bajpai Rashmi?Dubey 《Colloid and polymer science》2004,282(7):722-727
The chemical modification of Plantago psyllium mucilage (Psy), an anionic polysaccharide, was done by grafting polyacrylamide (PAM) chains to prepare a graft-copolymer (Psy-g-PAM). It was synthesized in the presence of nitrogen using ceric ammonium nitrate–nitric acid redox initiator and characterized by IR spectroscopy, scanning electron microscopy and viscosity measurements. This grafted copolymer was tested for its flocculation efficiency in textile wastewater by the standard Jar test method. The effects of polymer concentration, pH and contact time on the percentage removal of solid wastes [total dissolved solids (TDS) and suspended solids (SS)] and color from textile effluent are reported. The optimum dose was found to be 1.6 mg l–1, at which maximum solid removal (SS and TDS) was seen. The most suitable pH for TDS and color removal was neutral (7.0) and for SS removal alkaline pH (9.2) was found to be most suitable. The optimum treatment duration for solid waste removal was 5 h. The X-ray diffraction analysis of Psy-g-PAM and solid waste before and after treatment suggests the interaction of the solid waste and Psy-g-PAM copolymer. 相似文献
49.
A novel intercalating phenazine derivative (Pzn) was covalently linked to the 3-end of decathymidylate via a ribose residue of the dye. A fluorescence technique was used to study double helix formation by this conjugate with poly(rA) in aqueous solutions of neutral pH, at the presence of 0.1 and 1 M sodium ions. Proportionality between thermally induced changes in the fluorescence intensity of the free conjugate and bound one was revealed, that made it possible to calculate the helix-to-coil transition from fluorescence melting data using a simple equation. The transition curves were found to be in well conformity with those constructed from absorption measurements. It was shown that the attachment of Pzn significantly enhanced the stability of poly(rA) · (dT)10 duplex due to intercalation of the dye chromophore into the adenine strand. The temperature of half-dissociation was increased by 12°C, and the stabilizing increment of standard free energy was 3.2–3.6 kcal/mol at 37°C. 相似文献
50.
M. K. Pandey R. K. Dubey D. N. Tripathi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):275-279
The Classical Trajectory Monte Carlo (CTMC) Method has
been used to calculate the differential, partial and total single electron
capture cross sections for the collision of H+/D+ with Ca and Mg
atoms in the energy range of 1–100 keV. The differential cross sections
at angles near the diffraction limit (<0.1○) in both systems
show a forward peak followed by an asymptotic fall at higher angles. Total
and partial capture cross sections are found to be in good agreement with
the experimental observations. Oscillations in the partial capture cross sections have been explained due to the swapping
of the field electron.
Isotope effect in the electron transfer is reported to be negligible. 相似文献