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   452篇
  免费   3篇
  国内免费   9篇
系统科学   6篇
教育与普及   1篇
理论与方法论   8篇
现状及发展   88篇
研究方法   63篇
综合类   294篇
自然研究   4篇
  2021年   7篇
  2019年   2篇
  2018年   11篇
  2017年   7篇
  2016年   10篇
  2015年   7篇
  2014年   4篇
  2013年   8篇
  2012年   40篇
  2011年   61篇
  2010年   19篇
  2009年   3篇
  2008年   34篇
  2007年   41篇
  2006年   30篇
  2005年   35篇
  2004年   21篇
  2003年   21篇
  2002年   21篇
  2001年   7篇
  2000年   6篇
  1999年   4篇
  1995年   2篇
  1994年   3篇
  1993年   3篇
  1991年   2篇
  1990年   5篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1984年   2篇
  1983年   3篇
  1978年   1篇
  1977年   3篇
  1976年   1篇
  1975年   3篇
  1974年   2篇
  1973年   1篇
  1972年   4篇
  1971年   1篇
  1970年   1篇
  1969年   2篇
  1967年   1篇
  1966年   4篇
  1965年   1篇
  1964年   2篇
  1962年   1篇
  1958年   1篇
  1957年   1篇
  1945年   1篇
排序方式: 共有464条查询结果,搜索用时 187 毫秒
1.
2.
3.
4.
Introduction Micro-machined angular rate sensors or gyroscopes are used to measure the angular velocity of a moving ob- ject without an external reference. Low cost, high pre- cision gyroscopes find a large market in consumer products, automobiles, medica…  相似文献   
5.
6.
Earman (2018) has recently argued that the Principal Principle, a principle of rationality connecting objective chance and credence, is a theorem of quantum probability theory. This paper critiques Earman's argument, while also offering a positive proposal for how to understand the status of the Principal Principle in quantum probability theory.  相似文献   
7.
Nested clusters arise independently in graph partitioning and in the study of contours. We take a step toward unifying these two instances of nested clusters. We show that the graph theoretical tight clusters introduced by Dress, Steel, Moulton and Wu in 2010 are a special case of nested clusters associated to contours.  相似文献   
8.
9.
Rapidly proliferating tumor cells easily become hypoxic. This results in acquired stability towards treatment with anticancer drugs. Here, we show that cells grown at 0.1 % oxygen are more resistant towards treatment with the conventionally used anticancer drugs doxorubicin and cisplatin. The stimulation of apoptosis, as assessed by the number of cells in the SubG1 fraction of the cell cycle, release of cytochrome c into the cytosol, activation of caspase-3, and cleavage of PARP, was markedly suppressed under low oxygen content or when hypoxia was mimicked by deferoxamine. Hypoxia or deferoxamine treatment was accompanied by stabilization of the hypoxia-inducible factor (HIF-1). The downregulation of HIF-1 using siRNA technique restored cell sensitivity to treatment under hypoxic conditions to the levels detected under normoxic conditions. In contrast to cisplatin or doxorubicin, α-tocopheryl succinate (α-TOS), a compound that targets mitochondria, stimulated cell death irrespective of the oxygen concentration. Moreover, under hypoxic condition cell death induced by α-TOS was even enhanced. Thus, α-TOS can successfully overcome resistance to treatment caused by hypoxia, which makes α-TOS an attractive candidate for antitumor therapy via mitochondrial targeting.  相似文献   
10.
Genome-wide association studies (GWAS) are a standard approach for studying the genetics of natural variation. A major concern in GWAS is the need to account for the complicated dependence structure of the data, both between loci as well as between individuals. Mixed models have emerged as a general and flexible approach for correcting for population structure in GWAS. Here, we extend this linear mixed-model approach to carry out GWAS of correlated phenotypes, deriving a fully parameterized multi-trait mixed model (MTMM) that considers both the within-trait and between-trait variance components simultaneously for multiple traits. We apply this to data from a human cohort for correlated blood lipid traits from the Northern Finland Birth Cohort 1966 and show greatly increased power to detect pleiotropic loci that affect more than one blood lipid trait. We also apply this approach to an Arabidopsis thaliana data set for flowering measurements in two different locations, identifying loci whose effect depends on the environment.  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