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   648篇
  免费   33篇
  681篇
  2023年   6篇
  2022年   9篇
  2021年   11篇
  2020年   10篇
  2019年   13篇
  2018年   8篇
  2017年   13篇
  2016年   18篇
  2015年   26篇
  2014年   28篇
  2013年   51篇
  2012年   61篇
  2011年   59篇
  2010年   41篇
  2009年   28篇
  2008年   37篇
  2007年   40篇
  2006年   25篇
  2005年   22篇
  2004年   25篇
  2003年   25篇
  2002年   23篇
  2001年   6篇
  2000年   4篇
  1999年   3篇
  1998年   2篇
  1997年   3篇
  1996年   4篇
  1994年   3篇
  1993年   7篇
  1991年   2篇
  1990年   5篇
  1989年   3篇
  1987年   4篇
  1986年   5篇
  1985年   3篇
  1984年   8篇
  1983年   3篇
  1982年   3篇
  1981年   2篇
  1980年   3篇
  1978年   2篇
  1974年   4篇
  1973年   4篇
  1970年   3篇
  1969年   2篇
  1968年   4篇
  1964年   2篇
  1934年   1篇
  1932年   1篇
排序方式: 共有681条查询结果,搜索用时 0 毫秒
71.
Synchronization of chaotic low-dimensional systems has been a topic of much recent research. Such systems have found applications for secure communications. In this work we show how synchronization can be achieved in a high-dimensional chaotic neural network. The network used in our studies is an extension of the Hopfield Network, known as the Complex Hopfield Network (CHN). The CHN, also an associative memory, has both fixed point and limit cycle or oscillatory behavior. In the oscillatory mode, the network wanders chaotically from one stored pattern to another. We show how a pair of identical high-dimensional CHNs can be synchronized by communicating only a subset of state vector components. The synchronizability of such a system is characterized through simulations.  相似文献   
72.
73.

Background  

Candidate single nucleotide polymorphisms (SNPs) from genome-wide association studies (GWASs) were often selected for validation based on their functional annotation, which was inadequate and biased. We propose to use the more than 200,000 microarray studies in the Gene Expression Omnibus to systematically prioritize candidate SNPs from GWASs.  相似文献   
74.
The paper provides a comprehensive review of methodology for setting confidence intervals for the parameter of a Poisson distribution. The results are illustrated by a numerical example.  相似文献   
75.
76.
The purpose of this work was to establish ultrasonic storage modulus (G') as a novel parameter for characterizing protein-protein interactions (PPI) in high concentration protein solutions. Using an indigenously developed ultrasonic shear rheometer, G' for 20-120 mg/ml solutions of a monoclonal antibody (IgG(2)), between pH 3.0 and 9.0 at 4 mM ionic strength, was measured at frequency of 10 MHz. Our understanding of ultrasonic rheology indicated decrease in repulsive and increase in attractive PPI with increasing solution pH. To confirm this behavior, dynamic (DLS) and static (SLS) light scattering measurements were conducted in dilute solutions. Due to technical limitations, light scattering measurements could not be conducted in concentrated solutions. Mutual-diffusion coefficient, measured by DLS, increased with IgG(2) concentration at pH 4.0 and this trend reversed as pH was increased to 9.0. Second virial coefficient, measured by SLS, decreased with increasing pH. These observations were consistent with the nature of PPI understood from G' measurements. Ultrasonic rheology, DLS, and SLS measurements were also conducted under conditions of increased ionic strength. The consistency between rheology and light scattering analysis under various solution conditions established the utility of ultrasonic G' measurements as a novel tool for analyzing PPI in high protein concentration systems.  相似文献   
77.
A processed oligosaccharide mixture of buffalo milk induced significant stimulation of antibody, delayed-type hypersensitivity response to sheep red blood cells in BALB/c mice. This also stimulated non-specific immune response of the animals measured in terms of macrophage migration index. A novel pentasaccharide has been isolated from the oligosaccharide containing fraction having immunostimulant activity of buffalo milk. This compound was isolated by a combination of gel filtration chromatography, silica gel column chromatography of derivatised oligosaccharides while the homogeneity was confirmed by high performance liquid chromatography. The results of structural analyses, i.e. proton nuclear magnetic resonance, fast atom bombardment mass spectrometry, chemical transformations and degradations are consistent with the following structure: GlcNAcbeta(1-->3)Galbeta(1-->4)GlcNAcbeta(1-->3)Gal beta(1-->4)Glc  相似文献   
78.
This study was designed to examine the three-dimensional geometry of the head of the first metatarsal bone of the foot. Ninety-seven adult first metatarsal head (MTH1) bones were scanned using a laser scanner at 400 dpi. A best-fit ellipsoid was obtained from the articular surfaces of MTH1 for each size group using nonlinear unconstrained optimisation. Average root mean square errors between the articulating surfaces and the optimal fit surfaces of the bone specimens were between 0.29 and 0.42 mm. After classification based on sex and size groups, the profile provided a good fit to individual bones. Consideration of the thickness of cartilage overlying the metatarsal head (MTH) may further improve the fit. The proposed approach provides the basis for a design of an MTH hemi-arthroplasty that has good anatomical congruence with the native joint.  相似文献   
79.
80.
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