全文获取类型
收费全文 | 7399篇 |
免费 | 484篇 |
国内免费 | 529篇 |
专业分类
化学 | 563篇 |
晶体学 | 6篇 |
力学 | 467篇 |
综合类 | 75篇 |
数学 | 5560篇 |
物理学 | 1741篇 |
出版年
2023年 | 58篇 |
2022年 | 91篇 |
2021年 | 138篇 |
2020年 | 170篇 |
2019年 | 184篇 |
2018年 | 184篇 |
2017年 | 168篇 |
2016年 | 194篇 |
2015年 | 131篇 |
2014年 | 299篇 |
2013年 | 702篇 |
2012年 | 298篇 |
2011年 | 407篇 |
2010年 | 354篇 |
2009年 | 469篇 |
2008年 | 536篇 |
2007年 | 510篇 |
2006年 | 418篇 |
2005年 | 343篇 |
2004年 | 283篇 |
2003年 | 323篇 |
2002年 | 274篇 |
2001年 | 217篇 |
2000年 | 202篇 |
1999年 | 179篇 |
1998年 | 197篇 |
1997年 | 170篇 |
1996年 | 126篇 |
1995年 | 87篇 |
1994年 | 72篇 |
1993年 | 68篇 |
1992年 | 57篇 |
1991年 | 43篇 |
1990年 | 41篇 |
1989年 | 51篇 |
1988年 | 50篇 |
1987年 | 39篇 |
1986年 | 27篇 |
1985年 | 43篇 |
1984年 | 37篇 |
1983年 | 20篇 |
1982年 | 31篇 |
1981年 | 20篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 14篇 |
1977年 | 13篇 |
1976年 | 17篇 |
1974年 | 6篇 |
1973年 | 7篇 |
排序方式: 共有8412条查询结果,搜索用时 359 毫秒
91.
吴桂荣 《数学物理学报(A辑)》1998,18(1):116-120
该文对一般的随机变量序列及相当弱的系数条件研究了随机级数定义的整函数的奈望里纳特征函数,并证明了它是几乎必然无有限例外值的. 相似文献
92.
n阶变系数线性差分微分方程的解 总被引:1,自引:0,他引:1
利用Mikusi'nski算符域中变系数算符概念和相应的算符系数移动算符幂级数的概念和结果,获得初值条件下n阶变系数线性差分微分方程的解. 相似文献
93.
Keith Warren Julien C. Sprott Raymond C. Hawkins 《Nonlinear dynamics, psychology, and life sciences》2002,6(1):55-70
In recent years there has been considerable interest in the construction of nonlinear models of the dynamics of human behavior. In this exploratory article we argue that attempts at controlling problematic thoughts, emotions, or behaviors can lead to nonlinearity in mental/behavioral dynamics. We illustrate our model by fitting threshold autoregression models to self-recorded time series of the daily highs in intensity of anxiety and obsessive ruminations, kept by an individual in therapy for this problem. In our discussion, we raise the possibility that bifurcations that occur in this nonlinear model may offer insight into mental control paradoxes. 相似文献
94.
杨钟玄 《新疆大学学报(理工版)》2002,19(3):266-271
先对正项级数敛生判别法的粗细与强弱问题进行了辨析,然后建立了三个有关正项级数剑散判别的命题,分别比较了三组判别法之间的强弱关系。 相似文献
95.
Torbjörn Kolsrud 《Journal of Theoretical Probability》1989,2(4):399-418
We derive explicit isomorphism formulas between weighted Dirichlet integrals for harmonic functions and boundary Dirichlet forms. Applications yield results on traces of Markov processes and convergence quasieverywhere of harmonic functions. 相似文献
96.
97.
Serguei Foss Takis Konstantopoulos Stan Zachary 《Journal of Theoretical Probability》2007,20(3):581-612
We consider a modulated process S which, conditional on a background process X, has independent increments. Assuming that S drifts to −∞ and that its increments (jumps) are heavy-tailed (in a sense made precise in the paper), we exhibit natural
conditions under which the asymptotics of the tail distribution of the overall maximum of S can be computed. We present results in discrete and in continuous time. In particular, in the absence of modulation, the
process S in continuous time reduces to a Lévy process with heavy-tailed Lévy measure. A central point of the paper is that we make
full use of the so-called “principle of a single big jump” in order to obtain both upper and lower bounds. Thus, the proofs
are entirely probabilistic. The paper is motivated by queueing and Lévy stochastic networks. 相似文献
98.
Feng Dejun 《分析论及其应用》2003,19(4)
1 IntroductionForany 0 <λ <1 ,letνλ denotethedistributionof ∞n=0 εnλn wherethecoefficientsεnareeither0or1 ,chosenindependentlywithprobability12 foreach .Itistheinfiniteconvo lutionproductofthedistributions 12 (δ0 +δλn) ,givingrisetotheterm“infiniteBernoulliconvolution”orsimply“Bernoulliconvolution” .TheBernoulliconvolutioncanbeexpressedasaself similarmeasureνλsatisfyingtheequationνλ =12 νλ φ- 10 + 12 νλ φ- 11,( 1 .1 )whereφ0 (x) =λxand φ1(x) =λx + 1 .Thisme… 相似文献
99.
The main objects of study in this article are two classes of Rankin–Selberg L-functions, namely L(s,f×g) and L(s, sym2(g)× sym2(g)), where f,g are newforms, holomorphic or of Maass type, on the upper half plane, and sym2(g) denotes the symmetric square lift of g to GL(3). We prove that in general, i.e., when these L-functions are not divisible by L-functions of quadratic characters (such divisibility happening rarely), they do not admit any LandauSiegel zeros. Such zeros, which are real and close to s=1, are highly mysterious and are not expected to occur. There are corollaries of our result, one of them being a strong lower bound for special value at s=1, which is of interest both geometrically and analytically. One also gets this way a good bound onthe norm of sym2(g). 相似文献
100.
In this paper, we applied multifractal modeling techniques to analyze the traffic data collected from the Beijing Yuquanying. The results indicated that multifractal characteristics obviously exist in the traffic system; the degree of fractality of these traffic data tends to increase as the traffic system becomes congested; the Hölder exponent that measures the local rate of fractality may be used as indicators to predict the presence of the traffic congestion. 相似文献