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   126453篇
  免费   32590篇
  国内免费   1122篇
耳鼻咽喉   2684篇
儿科学   3607篇
妇产科学   3056篇
基础医学   6606篇
口腔科学   5455篇
临床医学   29702篇
内科学   30176篇
皮肤病学   3671篇
神经病学   14836篇
特种医学   4682篇
外国民族医学   1篇
外科学   21113篇
综合类   728篇
现状与发展   40篇
一般理论   30篇
预防医学   16753篇
眼科学   3122篇
药学   3066篇
中国医学   47篇
肿瘤学   10790篇
  2024年   760篇
  2023年   5190篇
  2022年   1377篇
  2021年   3358篇
  2020年   5649篇
  2019年   2673篇
  2018年   7536篇
  2017年   7812篇
  2016年   8426篇
  2015年   8637篇
  2014年   11207篇
  2013年   13201篇
  2012年   5521篇
  2011年   5247篇
  2010年   7722篇
  2009年   9950篇
  2008年   5041篇
  2007年   4057篇
  2006年   5095篇
  2005年   3601篇
  2004年   2988篇
  2003年   2638篇
  2002年   2413篇
  2001年   2429篇
  2000年   1770篇
  1999年   2264篇
  1998年   2376篇
  1997年   2188篇
  1996年   2178篇
  1995年   1960篇
  1994年   1310篇
  1993年   1153篇
  1992年   1180篇
  1991年   1083篇
  1990年   951篇
  1989年   923篇
  1988年   858篇
  1987年   729篇
  1986年   712篇
  1985年   643篇
  1984年   535篇
  1983年   534篇
  1982年   423篇
  1981年   357篇
  1980年   290篇
  1979年   264篇
  1978年   292篇
  1977年   277篇
  1976年   231篇
  1974年   230篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Gray platelet syndrome (GPS) is a rare (<1/1 000 000) and inherited platelet function disorder characterized by macrothrombocytopenia, α-granule deficiency, and hemorrhages. Bleeding intensity does not correlate with platelet count nor with functional test results. We hereby describe the perioperative bleeding prevention and management of a patient with GPS requiring multiple redo cardiac surgeries.  相似文献   
72.
Our objectives were to study the prevalence, risk factors for carriage, and transmission dynamics of extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae (ESBLPE) in a national survey of cattle. This was a point prevalence study conducted from July to October 2013 in Israel. Stool samples were collected from 1,226 cows in 123 sections on 40 farms of all production types. ESBLPE were identified in 291 samples (23.7%): 287 contained Escherichia coli and 4 contained Klebsiella pneumoniae. The number of ESBLPE-positive cows was the highest in quarantine stations and on fattening farms and was the lowest on pasture farms (P = 0.03). The number of ESBLPE-positive cows was the lowest in sections containing adult cows (age, >25 months) and highest in sections containing calves (age, <4 months) (P < 0.001). Infrastructure variables that were significant risk factors for ESBLPE carriage included crowding, a lack of manure cleaning, and a lack of a cooling (P < 0.001 for each), all of which were more common in sections containing calves. Antimicrobial prophylaxis was given almost exclusively to calves and was associated with a high number of ESBLPE carriers (P < 0.001). The 287 E. coli isolates were typed into 106 repetitive extragenic palindromic (REP)-PCR types and mostly harbored blaCTX-M-1 or blaCTX-M-9 group genes. The isolates on the six farms with ≥15 isolates of ESBLPE were of 4 to 7 different REP-PCR types, with one dominant type being harbored by about half of the isolates. Fourteen types were identified on more than one farm, with only six of the farms being adjacent to each other. The prevalence of ESBLPE carriage is high in calves in cowsheds where the use of antimicrobial prophylaxis is common. ESBLPE disseminate within cowsheds mainly by clonal spread, with limited intercowshed transmission occurring.  相似文献   
73.
74.
75.
76.
77.
78.
79.
ABSTRACT

Abortion is legal in South Africa, but negative abortion attitudes remain common and are poorly understood. We used nationally representative South African Social Attitudes Survey data to analyze abortion attitudes in the case of fetal anomaly and in the case of poverty from 2007 to 2016 (n = 20,711; ages = 16+). We measured correlations between abortion attitudes and these important predictors: religiosity, attitudes about premarital sex, attitudes about preferential hiring and promotion of women, and attitudes toward family gender roles. Abortion acceptability for poverty increased over time (b = 0.05, p < .001), but not for fetal anomaly (b = ?0.008, p = .284). Highly religious South Africans reported lower abortion acceptability in both cases (Odds Ratio (OR)anomaly = 0.85, p = .015; ORpoverty = 0.84, p = .02). Premarital sex acceptability strongly and positively predicted abortion acceptability (ORanomaly = 2.63, p < .001; ORpoverty = 2.46, p < .001). Attitudes about preferential hiring and promotion of women were not associated with abortion attitudes, but favorable attitudes about working mothers were positively associated with abortion acceptability for fetal anomaly ((ORanomaly = 1.09, p = .01; ORpoverty = 1.02, p = .641)). Results suggest negative abortion attitudes remain common in South Africa and are closely tied to religiosity, traditional ideologies about sexuality, and gender role expectations about motherhood.  相似文献   
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