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   1349篇
  免费   18篇
  国内免费   1篇
化学   61篇
晶体学   1篇
力学   14篇
综合类   3篇
数学   708篇
物理学   272篇
无线电   309篇
  2022年   1篇
  2021年   1篇
  2020年   2篇
  2019年   4篇
  2018年   5篇
  2017年   5篇
  2016年   5篇
  2015年   13篇
  2014年   18篇
  2013年   13篇
  2012年   61篇
  2011年   215篇
  2010年   206篇
  2009年   215篇
  2008年   194篇
  2007年   151篇
  2006年   107篇
  2005年   63篇
  2004年   30篇
  2003年   26篇
  2002年   18篇
  2001年   1篇
  1999年   1篇
  1998年   1篇
  1996年   2篇
  1993年   1篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1987年   2篇
  1986年   2篇
排序方式: 共有1368条查询结果,搜索用时 156 毫秒
101.
周旭东  兰逸君 《半导体光电》2009,30(2):284-285,290
设计并实现了一种CMOS图像传感器阵列的图像采集和处理系统,采用CMOS芯片KAC-9618采集图像,在FPGA的时序控制下,通过USB2.0传输控制芯片CY7C68013A来传输数据,然后在PC端进行处理.  相似文献   
102.
USB设备驱动程序设计   总被引:1,自引:0,他引:1  
本文介绍了使用DriverStudio软件开发USB设备驱动程序的方法,驱动程序的主要功能包括:使用端口O发送控制命令或读取少量数据,使用端口2进行大量数据传输,DriverSmdio软件自动产生驱动程序的框架及部分源程序;给出USB设备驱动程序的安装及调用方法.  相似文献   
103.
陈琛  廖丁毅 《电子科技》2009,22(12):29-33
采用高速USB接口连接计算机终端与UWB通信系统基带模块,设计并实现了USB接口电路,控制UWB通信系统基带模块与USB接口设备的数据传输,最终实现了终端电脑与UWB通信系统的数据传输。实际测试中,USB接口的速率约为300MB/s,达到了USB2.0规范所规定的高速传输的要求。  相似文献   
104.
董璐 《现代电视技术》2009,(11):124-128
本文介绍了新闻计费系统的架构及其特点,描述了利用JAVA技术实现基于Web的新闻计费系统,阐述了该系统所运用的关键技术。该系统能够实现对Avid系统的软件和硬件的分别计费和统计,对Avid系统的使用流程没有影响,具有较强的实用性和创新性。  相似文献   
105.
We describe the essential spectrum and prove the Mourre estimate for quantum particle systems interacting through k-body forces and creation-annihilation processes which do not preserve the number of particles. For this we compute the “Hamiltonian algebra” of the system, i.e. the C-algebra C generated by the Hamiltonians we want to study, and show that, as in the N-body case, it is graded by a semilattice. Hilbert C-modules graded by semilattices are involved in the construction of C. For example, if we start with an N-body system whose Hamiltonian algebra is CN and then we add field type couplings between subsystems, then the many-body Hamiltonian algebra C is the imprimitivity algebra of a graded Hilbert CN-module.  相似文献   
106.
In this paper we investigate when various Banach algebras associated to a locally compact group G have the weak or weak fixed point property for left reversible semigroups. We proved, for example, that if G is a separable locally compact group with a compact neighborhood of the identity invariant under inner automorphisms, then the Fourier-Stieltjes algebra of G has the weak fixed point property for left reversible semigroups if and only if G is compact. This generalizes a classical result of T.C. Lim for the case when G is the circle group T.  相似文献   
107.
We prove that if H is a Hilbert space then the Schatten (trace) class operators on H has the weak fixed point property for left reversible semigroups. This answered positively a problem raised by A.T.-M. Lau. We also prove that if M is a finite von Neumann algebra then any nonempty bounded convex subset of the non-commutative L1-space associated to M that is compact for the measure topology has the fixed point property for left reversible semigroups.  相似文献   
108.
The purpose of this paper is to exhibit the relations between some basic results derived from the two kinds of topologies (namely the (ε,λ)-topology and the stronger locally L0-convex topology) for a random locally convex module. First, we give an extremely simple proof of the known Hahn-Banach extension theorem for L0-linear functions as well as its continuous variant. Then we give the relations between the hyperplane separation theorems in [D. Filipovi?, M. Kupper, N. Vogelpoth, Separation and duality in locally L0-convex modules, J. Funct. Anal. 256 (2009) 3996-4029] and a basic strict separation theorem in [T.X. Guo, H.X. Xiao, X.X. Chen, A basic strict separation theorem in random locally convex modules, Nonlinear Anal. 71 (2009) 3794-3804]: in the process we also obtain a very useful fact that a random locally convex module with the countable concatenation property must have the same completeness under the two topologies. As applications of the fact, we prove that most of the previously established principal results of random conjugate spaces of random normed modules under the (ε,λ)-topology are still valid under the locally L0-convex topology, which considerably enriches financial applications of random normed modules.  相似文献   
109.
The notion of a regular operator with compact supports between function spaces is introduced. On that base we obtain a characterization of absolute extensors for 0-dimensional spaces in terms of regular extension operators having compact supports. Milyutin maps are also considered and it is established that some topological properties, like paracompactness, metrizability and κ-metrizability, are preserved under Milyutin maps.  相似文献   
110.
By a ball-covering B of a Banach space X, we mean that B is a collection of open (or closed) balls off the origin whose union contains the unit sphere SX of X; and X is said to have the ball-covering property (BCP) provided it admits a ball-covering by countably many balls. In this note we give a natural example showing that the ball-covering property of a Banach space is not inherited by its subspaces; and we present a sharp quantitative version of the recent Fonf and Zanco renorming result saying that if the dual X of X is w separable, then for every ε>0 there exist a (1+ε)-equivalent norm on X, and an R>0 such that in this new norm SX admits a ball-covering by countably many balls of radius R. Namely, we show that R=R(ε) can be taken arbitrarily close to (1+ε)/ε, and that for X=?1[0,1] the corresponding R cannot be equal to 1/ε. This gives the sharp order of magnitude for R(ε) as ε→0.  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