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   2587892篇
  免费   185623篇
  国内免费   7583篇
耳鼻咽喉   34305篇
儿科学   85228篇
妇产科学   71579篇
基础医学   363709篇
口腔科学   69701篇
临床医学   234596篇
内科学   515864篇
皮肤病学   62536篇
神经病学   213511篇
特种医学   99925篇
外国民族医学   736篇
外科学   386516篇
综合类   50401篇
现状与发展   5篇
一般理论   968篇
预防医学   196210篇
眼科学   56670篇
药学   188013篇
  9篇
中国医学   5337篇
肿瘤学   145279篇
  2021年   19997篇
  2019年   20632篇
  2018年   29306篇
  2017年   22604篇
  2016年   26231篇
  2015年   29516篇
  2014年   40458篇
  2013年   60446篇
  2012年   80252篇
  2011年   84515篇
  2010年   51018篇
  2009年   49152篇
  2008年   79034篇
  2007年   83860篇
  2006年   85582篇
  2005年   81739篇
  2004年   78743篇
  2003年   76053篇
  2002年   73341篇
  2001年   128422篇
  2000年   131340篇
  1999年   110510篇
  1998年   31256篇
  1997年   27921篇
  1996年   28220篇
  1995年   27387篇
  1994年   25069篇
  1993年   23424篇
  1992年   85164篇
  1991年   81564篇
  1990年   78789篇
  1989年   76065篇
  1988年   69473篇
  1987年   68000篇
  1986年   63542篇
  1985年   60512篇
  1984年   44941篇
  1983年   37946篇
  1982年   22456篇
  1981年   19985篇
  1979年   38959篇
  1978年   27441篇
  1977年   23252篇
  1976年   21498篇
  1975年   22815篇
  1974年   26786篇
  1973年   25370篇
  1972年   23750篇
  1971年   21958篇
  1970年   20185篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
101.
Abstract

Background

Across the spectrum of patient care for opioid overdose, an important, yet frequently overlooked feature is the bystander, or witness to the overdose event. For other acute medical events such as cardiac arrest and stroke, research supports that the presence of a bystander is associated with better outcomes. Despite the similarities, however, this well-established conceptual framework has yet to be applied in the context of overdose patient outcomes. The objective of this study was to assess the association between the nature of the bystander-patient relationship and prehospital care measures in patients being treated for opioid overdose.  相似文献   
102.
locStra is an ‐package for the analysis of regional and global population stratification in whole‐genome sequencing (WGS) studies, where regional stratification refers to the substructure defined by the loci in a particular region on the genome. Population substructure can be assessed based on the genetic covariance matrix, the genomic relationship matrix, and the unweighted/weighted genetic Jaccard similarity matrix. Using a sliding window approach, the regional similarity matrices are compared with the global ones, based on user‐defined window sizes and metrics, for example, the correlation between regional and global eigenvectors. An algorithm for the specification of the window size is provided. As the implementation fully exploits sparse matrix algebra and is written in C++, the analysis is highly efficient. Even on single cores, for realistic study sizes (several thousand subjects, several million rare variants per subject), the runtime for the genome‐wide computation of all regional similarity matrices does typically not exceed one hour, enabling an unprecedented investigation of regional stratification across the entire genome. The package is applied to three WGS studies, illustrating the varying patterns of regional substructure across the genome and its beneficial effects on association testing.  相似文献   
103.
104.
105.
106.
107.
108.
To control agricultural pests and meet the increasing food demands, pesticides use has been increased substantially over time. Although pesticides are relatively specific to their targets, they can affect non-target organisms and are hazardous for the population around the application areas particularly to the individuals engaged in different types of agricultural activities. This situation is worse in developing and under-developed countries where personal protective equipment is merely used and regulatory guidelines are hardly practiced. In the present study, DNA damage in women exposed to pesticides while picking cotton with bare hands was assessed using single cell gel electrophoresis assay or comet assay. The presence of pesticides in blood serum of exposed individuals was also analyzed using high-performance liquid chromatography. Blood samples were collected from 138 (69 exposed and 69 control) randomly selected females from a major cotton growing area (Bahawalpur District) of the Punjab province of Pakistan. DNA damage, as determined by the mean comet tail length, was significantly higher (p?p?相似文献   
109.
110.
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