全文获取类型
收费全文 | 6726篇 |
免费 | 277篇 |
国内免费 | 134篇 |
专业分类
化学 | 1104篇 |
晶体学 | 54篇 |
力学 | 566篇 |
综合类 | 28篇 |
数学 | 2616篇 |
物理学 | 2769篇 |
出版年
2024年 | 4篇 |
2023年 | 33篇 |
2022年 | 103篇 |
2021年 | 121篇 |
2020年 | 118篇 |
2019年 | 100篇 |
2018年 | 95篇 |
2017年 | 118篇 |
2016年 | 148篇 |
2015年 | 136篇 |
2014年 | 244篇 |
2013年 | 479篇 |
2012年 | 237篇 |
2011年 | 291篇 |
2010年 | 259篇 |
2009年 | 423篇 |
2008年 | 408篇 |
2007年 | 446篇 |
2006年 | 397篇 |
2005年 | 300篇 |
2004年 | 228篇 |
2003年 | 286篇 |
2002年 | 274篇 |
2001年 | 233篇 |
2000年 | 297篇 |
1999年 | 196篇 |
1998年 | 250篇 |
1997年 | 108篇 |
1996年 | 92篇 |
1995年 | 87篇 |
1994年 | 51篇 |
1993年 | 65篇 |
1992年 | 70篇 |
1991年 | 40篇 |
1990年 | 29篇 |
1989年 | 28篇 |
1988年 | 46篇 |
1987年 | 45篇 |
1986年 | 34篇 |
1985年 | 57篇 |
1984年 | 44篇 |
1983年 | 18篇 |
1982年 | 24篇 |
1981年 | 14篇 |
1980年 | 7篇 |
1979年 | 15篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1973年 | 6篇 |
排序方式: 共有7137条查询结果,搜索用时 15 毫秒
51.
Automatic detection and identification of shocks in Gaussian state‐space models: a Bayesian approach
An automatic monitoring and intervention algorithm that permits the supervision of very general aspects in an univariate linear Gaussian state–space model is proposed. The algorithm makes use of a model comparison and selection approach within a Bayesian framework. In addition, this algorithm incorporates the possibility of eliminating earlier interventions when subsequent evidence against them comes to light. Finally, the procedure is illustrated with two empirical examples taken from the literature. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
52.
Vee Ming Ng 《Journal of multivariate analysis》2002,83(2):409
Bayesian inference is considered for the seemingly unrelated regressions with an elliptically contoured error distribution. We show that the posterior distribution of the regression parameters and the predictive distribution of future observations under elliptical errors assumption are identical to those obtained under independently distributed normal errors when an improper prior is used. This gives inference robustness with respect to departures from the reference case of independent sampling from the normal distribution. 相似文献
53.
Howel Tong 《应用数学学报(英文版)》2002,18(2):177-184
Abstract I reflect upon the development of nonlinear time series analysis since 1990 by focusing on five majorareas of development. These areas include the interface between nonlinear time series analysis and chaos,thenonparametric/semiparametric approach,nonlinear state space modelling,financial time series and nonlinearmodelling of panels of time series. 相似文献
54.
F.J. Olmo A. Quirantes A. Alcntara H. Lyamani L. Alados-Arboledas 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,100(1-3):305-314
There is experimental evidence that the non-sphericity of certain atmospheric particles can cause scattering properties different from those predicted by standard Mie theory. Numerous studies indicate the need to consider the presence of non-spherical particles in modeling the optical properties of atmospheric aerosols. On the other hand, natural aerosols show a great variety of shapes, making difficult a realistic choice of a particle shape (or shape mixture) model. In this paper, we test a parameterization of the particle shape in the retrieval of size distribution, phase function, single scattering albedo and asymmetry parameter from direct and sky-radiance measurements. For this purpose we have substituted the Kernel based on the Mie theory included in the model SKYRAD.PACK by one derived for non-spherical particles. The method is applied under different atmospheric conditions, including Saharan dust outbreak, polluted and local mineral episodes. We compare the results with those obtained by the well known spheroids algorithm used in the AERONET network. 相似文献
55.
The critical limit of the eight-vertex model eigenvectors obtained by means of the generalized Bethe Ansatz is shown to give the six-vertex eigenvectors as constructed in a previous paper by two of the authors. Furthermore, an explicit mapping is established between these eigenvectors and the usual Bethe Ansatz eigenvectors of the six-vertex model. This allows one to show that the indexv labeling the eight-vertex eigenstates becomes exactly the third component of the total spin in the critical limit. 相似文献
56.
It has already been argued that a classical (three-dimensional) Coulomb fluid confined between two parallel walls exhibits ideal gas features when the distance between the walls becomes small; this is confirmed in the present paper. Two-dimensional models of Coulomb fluids (with a logarithmic interaction), confined in a strip, are also studied. These models do not become ideal gases in the narrow strip limit. The correlation functions are also studied. There is a special temperature at which exact results are obtained. At that temperature, the two-dimensional, two-component plasma (two-dimensional Coulomb gas), which is a conductor when unconfined, becomes a dielectric as soon as it is confined in a strip of noninfinite width. This can be understood as a displacement of the Kosterlitz-Thouless transition by the confinement. 相似文献
57.
58.
Ajay K. Saini Clifford M. Carlin Howard H. Patterson 《Journal of polymer science. Part A, Polymer chemistry》1992,30(3):419-427
New model compounds for poly[N,N′-bis(phenoxyphenyl)pyromellitimide] have been synthesized in order to investigate the formation of imine bonds which are proposed to form during the curing process and lead to crosslinking in the bulk polymer. Raman studies show that terminal amines can react with imide carbonyls during curing to form C?N bonds. The Raman band due to C?N appears at 1656 cm?1 and the band due to C?O closest to the imine bond is observed at 1742 cm?1. These results are in agreement with previously published results on vapor deposited polyimide films. 相似文献
59.
This paper introduces a profile empirical likelihood and a profile conditionally empirical likelihood to estimate the parameter
of interest in the presence of nuisance parameters respectively for the parametric and semiparametric models. It is proven
that these methods propose some efficient estimators of parameters of interest in the sense of least-favorable efficiency.
Particularly, for the decomposable semiparametric models, an explicit representation for the estimator of parameter of interest
is derived from the proposed nonparametric method. These new estimations are different from and more efficient than the existing
estimations. Some examples and simulation studies are given to illustrate the theoretical results.
The first author is supported by NNSF projects (10371059 and 10171051) of China. The second author is supported by a grant
from The Research Grants Council of the Hong Kong Special Administrative Region, China (#HKU7060/04P). The third author is
supported by the University Research Committee of the University of Hong Kong and a grant from the Research Grants Council
of the Hong Kong Special Administrative Region, China (Project No. HKU7323/01M). 相似文献
60.
Fabio Schoen 《Journal of Global Optimization》1994,4(1):17-35
In this paper a new algorithm is proposed for global optimization problems. The main idea is that of modifying a standard clustering approach by sequentially sampling the objective function while adaptively deciding an appropriate sample size. Theoretical as well as computational results are presented. 相似文献