全文获取类型
收费全文 | 22249篇 |
免费 | 1752篇 |
国内免费 | 1583篇 |
专业分类
化学 | 1464篇 |
晶体学 | 39篇 |
力学 | 2051篇 |
综合类 | 348篇 |
数学 | 19084篇 |
物理学 | 2598篇 |
出版年
2024年 | 29篇 |
2023年 | 190篇 |
2022年 | 243篇 |
2021年 | 301篇 |
2020年 | 452篇 |
2019年 | 496篇 |
2018年 | 549篇 |
2017年 | 627篇 |
2016年 | 644篇 |
2015年 | 469篇 |
2014年 | 948篇 |
2013年 | 1819篇 |
2012年 | 1065篇 |
2011年 | 1196篇 |
2010年 | 1103篇 |
2009年 | 1509篇 |
2008年 | 1554篇 |
2007年 | 1579篇 |
2006年 | 1369篇 |
2005年 | 1112篇 |
2004年 | 994篇 |
2003年 | 1054篇 |
2002年 | 889篇 |
2001年 | 665篇 |
2000年 | 659篇 |
1999年 | 604篇 |
1998年 | 563篇 |
1997年 | 512篇 |
1996年 | 388篇 |
1995年 | 305篇 |
1994年 | 250篇 |
1993年 | 205篇 |
1992年 | 196篇 |
1991年 | 161篇 |
1990年 | 135篇 |
1989年 | 79篇 |
1988年 | 69篇 |
1987年 | 65篇 |
1986年 | 59篇 |
1985年 | 88篇 |
1984年 | 72篇 |
1983年 | 47篇 |
1982年 | 54篇 |
1981年 | 51篇 |
1980年 | 33篇 |
1979年 | 33篇 |
1978年 | 33篇 |
1977年 | 26篇 |
1976年 | 15篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
1.
2.
In this paper, we study the Holder regularity of weak solutions to the Dirichlet problem associated with the regional fractional Laplacian (-△)αΩ on a bounded open set Ω ■R(N ≥ 2) with C(1,1) boundary ■Ω. We prove that when f ∈ Lp(Ω), and g ∈ C(Ω), the following problem (-△)αΩu = f in Ω, u = g on ■Ω, admits a unique weak solution u ∈ W(α,2)(Ω) ∩ C(Ω),where p >N/2-2α and 1/2< α < 1. To solve this problem, we consider it into two special cases, i.e.,g ≡ 0 on ■Ω and f ≡ 0 in Ω. Finally, taking into account the preceding two cases, the general conclusion is drawn. 相似文献
3.
4.
The chiral phase transition and equation of state are studied within a novel self-consistent mean-field approximation of the two-flavor Nambu-Jona-Lasinio model. In this newly developed model, modifications to the chemical μ and chiral chemical \begin{document}$\mu_5$\end{document} ![]()
![]()
potentials are naturally included by introducing vector and axial-vector channels from Fierz-transformed Lagrangian to the standard Lagrangian. In the proper-time scheme, the chiral phase transition is a crossover in the \begin{document}$T-\mu$\end{document} ![]()
![]()
plane. However, when \begin{document}$\mu_5$\end{document} ![]()
![]()
is incorporated, our study demonstrates that a first order phase transition may emerge. Furthermore, the chiral imbalance will soften the equation of state of quark matter. The mass-radius relationship and tidal deformability of quark stars are calculated. The maximum mass and radius decrease as \begin{document}$\mu_5$\end{document} ![]()
![]()
increases. Our study also indicates that the vector and axial-vector channels exhibit an opposite influence on the equation of state. 相似文献
5.
6.
Given a graph sequence denote by T3(Gn) the number of monochromatic triangles in a uniformly random coloring of the vertices of Gn with colors. In this paper we prove a central limit theorem (CLT) for T3(Gn) with explicit error rates, using a quantitative version of the martingale CLT. We then relate this error term to the well-known fourth-moment phenomenon, which, interestingly, holds only when the number of colors satisfies . We also show that the convergence of the fourth moment is necessary to obtain a Gaussian limit for any , which, together with the above result, implies that the fourth-moment condition characterizes the limiting normal distribution of T3(Gn), whenever . Finally, to illustrate the promise of our approach, we include an alternative proof of the CLT for the number of monochromatic edges, which provides quantitative rates for the results obtained in [7]. 相似文献
7.
8.
9.
《Operations Research Letters》2022,50(2):107-114
We investigate the value of an optimal transportation problem with the maximization objective as a function of costs and vectors of production and consumption. The value is concave in production. For generic costs, the numbers of linearity domains and peak points are independent of costs and consumption. The peak points are determined by an auxiliary assignment problem. The volumes of the linearity domains are independent of costs while their dependence on consumption can be expressed via the multinomial distribution. 相似文献
10.