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   100977篇
  免费   7067篇
  国内免费   329篇
耳鼻咽喉   1290篇
儿科学   2582篇
妇产科学   2342篇
基础医学   12567篇
口腔科学   2127篇
临床医学   9924篇
内科学   21941篇
皮肤病学   1094篇
神经病学   8758篇
特种医学   3399篇
外国民族医学   3篇
外科学   16331篇
综合类   1416篇
现状与发展   1篇
一般理论   75篇
预防医学   8011篇
眼科学   2700篇
药学   6432篇
中国医学   144篇
肿瘤学   7236篇
  2023年   416篇
  2022年   721篇
  2021年   1691篇
  2020年   926篇
  2019年   1642篇
  2018年   1952篇
  2017年   1441篇
  2016年   1600篇
  2015年   1881篇
  2014年   2781篇
  2013年   4391篇
  2012年   6286篇
  2011年   6558篇
  2010年   3662篇
  2009年   3394篇
  2008年   6198篇
  2007年   6887篇
  2006年   6572篇
  2005年   6725篇
  2004年   6550篇
  2003年   6165篇
  2002年   6136篇
  2001年   791篇
  2000年   557篇
  1999年   770篇
  1998年   1286篇
  1997年   1144篇
  1996年   968篇
  1995年   968篇
  1994年   850篇
  1993年   744篇
  1992年   567篇
  1991年   513篇
  1990年   449篇
  1989年   464篇
  1988年   436篇
  1987年   450篇
  1986年   448篇
  1985年   498篇
  1984年   706篇
  1983年   756篇
  1982年   978篇
  1981年   917篇
  1980年   869篇
  1979年   450篇
  1978年   530篇
  1977年   580篇
  1976年   491篇
  1975年   429篇
  1974年   340篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
AIMS: Nicotine dependence is a highly heritable disorder associated with severe medical morbidity and mortality. Recent meta-analyses have found novel genetic loci associated with cigarettes per day (CPD), a proxy for nicotine dependence. The aim of this paper is to evaluate the importance of phenotype definition (i.e. CPD versus Fagerstr?m Test for Cigarette Dependence (FTCD) score as a measure of nicotine dependence) on genome-wide association studies of nicotine dependence. DESIGN: Genome-wide association study. SETTING: Community sample. PARTICIPANTS: A total of 3365 subjects who had smoked at least one cigarette were selected from the Study of Addiction: Genetics and Environment (SAGE). Of the participants, 2267 were European Americans, 999 were African Americans. MEASUREMENTS: Nicotine dependence defined by FTCD score ≥4, CPD. FINDINGS: The genetic locus most strongly associated with nicotine dependence was rs1451240 on chromosome 8 in the region of CHRNB3 [odds ratio (OR)?=?0.65, P?=?2.4?×?10(-8) ]. This association was further strengthened in a meta-analysis with a previously published data set (combined P?=?6.7?×?10(-16) , total n?=?4200). When CPD was used as an alternate phenotype, the association no longer reached genome-wide significance (β?=?-0.08, P?=?0.0004). CONCLUSIONS: Daily cigarette consumption and the Fagerstrom Test for Cigarette Dependence show different associations with polymorphisms in genetic loci.  相似文献   
992.
993.
994.
995.
996.
Bacterial conjugate vaccines are based on the principle of coupling immunogenic bacterial capsular polysaccharides to a carrier protein to facilitate the induction of memory T-cell responses. Following the success of Haemophilus influenzae type b conjugate vaccines in the 1980s, conjugate vaccines for Streptococcus pneumoniae and Neisseria meningitidis infections were developed and proven to be effective in protecting children against invasive disease. In this review, the use of conjugate vaccines in human newborns is discussed. Neonatal Haemophilus influenzae type b and pneumococcal conjugate vaccination schedules have been trialed and proven to be safe, with the majority of studies demonstrating no evidence for the induction of immune tolerance. Whether their neonatal administration also results in an earlier induction of clinical protection in the first 2–3 critical months of life is still to be demonstrated.  相似文献   
997.
998.
999.
Scenarios simulating real-world risk situations have proven effective for substance use intervention methods and could potentially prove useful as an HIV-prevention method. This study explored qualitatively the development and use of such “in-the-moment” methods. We interviewed 97 moderate-drinking women (50 % Caucasian) after participation in an experiment requiring that they project themselves into a risky-sex scenario. Most participants (58 %) reported experiencing the scenario as a reflective tool characterized by two primary themes: (1) increased awareness of risk and (2) contemplation of behavior change. Findings suggest that “in-the-moment” methods depicting real-world risk situations and providing opportunities to reflect about behavioral choices and subsequent outcomes could prove a useful adjunct to HIV/AIDS-prevention interventions. Such methods could potentially augment existing prevention protocols.  相似文献   
1000.
This study examined health care utilization pre- and post-referral to a behaviorally based treatment program for feeding difficulties in children. Physician contacts and associated costs for a feeding clinic group (n = 490) and a group of matched population controls (n = 1,548) were examined across a 3-year period. Children with feeding difficulties had an increased frequency of physician visits and higher costs compared to controls. A subsample (n = 86) of clinic children revealed that successful behavioral feeding intervention resulted in a change in health care utilization, as demonstrated by a reduction in physician visits.  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