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101.
The purpose of this paper is to present a general stochastic calculus
approach to insider trading. We consider a market driven by a standard Brownian
motion $B(t)$ on a filtered probability space $\displaystyle
(\Omega,\F,\left\{\F\right\}_{t\geq 0},P)$ where the coefficients are
adapted to a filtration ${\Bbb G}=\left\{\G_t\right\}_{0\leq t\leq T}$,
with $\F_t\subset\G_t$ for all $t\in [0,T]$, $T>0$ being a fixed terminal time.
By
an {\it insider} in this market we
mean a person who has access to a filtration (information)
$\displaystyle{\Bbb H}=\left\{\H_t\right\}_{0\leq t\leq T}$ which is strictly
bigger than the filtration
$\displaystyle{\Bbb G}=\left\{\G_t\right\}_{0\leq t\leq T}$.
In this context an insider strategy is represented by an
$\H_t$-adapted process
$\phi(t)$ and we interpret all anticipating integrals as
the forward integral defined in
[23] and [25].
We consider an optimal portfolio problem with
general utility for an insider with access to a general information
$\H_t \supset\G_t$ and show that if
an optimal insider portfolio $\pi^*(t)$ of this problem exists, then
$B(t)$ is an $\H_t$-semimartingale, i.e. the enlargement
of filtration property holds. This is a converse of previously
known results in this field.
Moreover, if $\pi^*$ exists
we obtain an explicit expression in terms of $\pi^*$ for the
semimartingale decomposition of $B(t)$ with respect to $\H_t$.
This is a generalization
of results in [16], [20] and [2]. 相似文献
102.
Anna Krebs Barbara Starczewska Helena Puzanowska-Tarasiewicz Joanna Sledz 《Analytical sciences》2006,22(6):829-833
Three simple spectrophotometric methods have been described for the assay of olanzapine in its pure and pharmaceutical formulations. The direct method (A) is based on the drug oxidation with excess of N-bromosuccinimide in acidic medium and the two indirect methods (B and C) are based on the oxidation of the drug with excess of N-bromosuccinimide and cerium(IV)sulfate, followed by the reaction of the unconsumed oxidants with celestine blue. The calibration graphs were linear over the range 10 - 120 microg mL(-1) (method A), 0.5 - 6.0 microg mL(-1) (method B) and 0.6 - 3.0 microg mL(-1) (method C). After validation, the proposed methods were successfully applied to assay of olanzapine in its commercial tablets with mean percentage recoveries of 101.23 +/- 0.10, 96 +/- 0.10 and 94 +/- 0.04%. The mechanism of olanzapine oxidation with N-bromosuccinimide was also proposed. 相似文献
103.
Optical probes of solution-produced glasses yield valuable information about the local structure and dynamics of the host glass systems. We report lifetime results for europium excited states in a series of sol–gel-produced bioactive glasses with the composition CaxP0.06Si0.94?xO2 (0.11<x<0.35). The excited state lifetimes are very narrowly distributed about a mean value, leading to nearly single exponential decay curves. A rate equation model is used to study the effects of calcium concentration and temperature on the decay rates. While the presence of calcium in the glass samples greatly enhances the luminescence, over the concentration range tested, no significant difference in the decay times was measured. Over the temperature range 77–300 K about 20% and 30% increases in the decay rates of the 5D0 and 5D1 levels were measured, respectively. 相似文献
104.
105.
106.
107.
The rate of disappearance of solvated electrons by reaction with fluorobenzene in ammonia is accelerated by small concentrations of methanol; it also has a “negative activation energy” depending on the methanol concentration. The kinetic data suggest an exothermic electron attachment-detachment equilibrium with the fluorobenzene followed by a slower reaction of the electron adduct with the proton donating methanol. 相似文献
108.
109.
Wang Jian-qi Manijeh Mohraz Edgar Heilbronner Adolf Krebs Karin Schütz Jürgen Voss Brigitte Kpke 《Helvetica chimica acta》1983,66(3):801-808
The He(Iα) photoelectron (PE.) spectra of a series of substituted 1,2-dithietes have been recorded and assigned with respect to the orbital sequence derived from an STO-3G model calculation and by correlation with the PE. spectra of related compounds. The results provide additional support for the presence of a closed, four-membered ring moiety in all the 1,2-dithietes investigated. In all cases the two highest occupied molecular orbitals are b2(π)= HOMO, a2(π), with exception of 3,4-bis(trifluoromethyl)-1,2-dithiete where the sequence b2(π), a2(π) or a2(π), b2(π) is uncertain. 相似文献
110.