首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13874篇
  免费   273篇
  国内免费   156篇
化学   898篇
晶体学   19篇
力学   141篇
综合类   6篇
数学   12387篇
物理学   852篇
  2023年   39篇
  2022年   44篇
  2021年   49篇
  2020年   81篇
  2019年   325篇
  2018年   336篇
  2017年   214篇
  2016年   186篇
  2015年   162篇
  2014年   307篇
  2013年   811篇
  2012年   373篇
  2011年   751篇
  2010年   584篇
  2009年   920篇
  2008年   1083篇
  2007年   1122篇
  2006年   834篇
  2005年   565篇
  2004年   498篇
  2003年   418篇
  2002年   291篇
  2001年   259篇
  2000年   259篇
  1999年   314篇
  1998年   295篇
  1997年   220篇
  1996年   312篇
  1995年   304篇
  1994年   278篇
  1993年   232篇
  1992年   187篇
  1991年   119篇
  1990年   129篇
  1989年   120篇
  1988年   91篇
  1987年   108篇
  1986年   109篇
  1985年   141篇
  1984年   97篇
  1983年   83篇
  1982年   133篇
  1981年   104篇
  1980年   98篇
  1979年   59篇
  1978年   81篇
  1977年   76篇
  1976年   68篇
  1975年   14篇
  1974年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
We develop a new joint cure rate model for longitudinal and survival data. The model allows for multiple longitudinal markers as well as a cure structure for the survival component based on the promotion time cure rate model, as described in Ibrahim et al. (Bayesian Survival Analysis, Springer, New York, 2001). Several characteristics and properties of the new model are discussed and examined. A real dataset from a melanoma clinical trial is given to demonstrate the methodology.  相似文献   
102.
The notions of “labelled set” and “numerosity” are introduced to generalize the counting process of finite sets. The resulting numbers, called numerosities, are then used to develop nonstandard analysis. The existence of a numerosity function is equivalent to the existence of a selective ultrafilter, hence it is independent of the axioms of ZFC.  相似文献   
103.
Summary. We prove that - under certain conditions - measurable solutions $f$ of the functional equation $f(x)=h(x,y,f(g_{1}(x,y)),\ldots,f(g_{n}(x,y))),\quad(x,y)\in D \subset \mathbb{R}^{s} \times \mathbb{R}^{l}$ are continuous, even if $1\le l\le s$. As a tool we introduce new classes of functions which - roughly speaking - interpolate between continuous and Lebesgue measurable functions. Connection between these classes are also investigated.  相似文献   
104.
We construct nine rank five incidence geometries that are firm and residually connected and on which the Mathieu group M22 acts flag-transitively. The constructions use mainly objects arising from the Steiner systemS(3, 6, 22). One of these geometries was constructed by Meixner and Pasini in [10]. Three of them are obtained from the geometry of Meixner and Pasini using doubling (see [8] or [12]) or similar constructions. The remaining five are new and four of them have a star diagram. These latter four geometries are constructed using special partitions of the 22 points of the Steiner system S(3, 6, 22).  相似文献   
105.
Summary The detachment of a rubber matrix from a rigid inclusion under monotonic loading and at subsequent relaxation is investigated within two dimensional analysis. Examined are stress–strain experimental data acquired with the help of a test bed equipped with a digital image-acquisition device. The influence of the interfacial bonding strength and the particle size on the detachment process is analyzed. The influence of the interfacial bonding strength is visible in the stress–strain diagram of loading and in the recorded images. The relaxation test reveals no influence of the bonding strength on the stress-relaxation. However, the image analysis indicates a secondary transient creep of the contour of detachment, which depends on the interfacial bonding.  相似文献   
106.
The aim of this note is to generalize and apply results on matrix continued fractions representing the solution of discrete matrix Riccati equations. Assuming uniform bounds for the norm of the matrix coefficients of the continued fraction, the minimal and maximal solutions of the corresponding algebraic Riccati equation can be accurately enclosed.  相似文献   
107.
研究了钍与5-(对羧基苯偶氮)-8-羟基喹啉(5-CPAHQ)的显色反应条件:在阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)存在下,pH4.4-5.4缓冲介质中,形成稳定的橙红色络合物,最大吸收波长为490nm,ε=1.10×105L·mol-1·cm-1,钍在0-9μg/25mL范围内符合比尔定律。用TBP萃淋树脂分离,该方法可用于测定矿石中的微量钍。  相似文献   
108.
In this paper we introduce invariants of semi-free Hamiltonian actions of S1 on compact symplectic manifolds using the space of solutions to certain gauge theoretical equations. These equations generalise both the vortex equations and the holomorphicity equation used in Gromov-Witten theory. In the definition of the invariants we combine ideas coming from gauge theory and the ideas underlying the construction of Gromov-Witten invariants.  相似文献   
109.
Let p a prime, X = SL2(pa) and K = GF(pa). For S a Sylow p-subgroup of X, we explicitly describe the structure of the commutator series of S on each of the irreducible KX-modules.Received: 28 April 2004  相似文献   
110.
The surface body is a generalization of the floating body. Its relation to p-affine surface area is studied.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号