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   28150篇
  免费   2364篇
  国内免费   686篇
耳鼻咽喉   140篇
儿科学   776篇
妇产科学   621篇
基础医学   1159篇
口腔科学   270篇
临床医学   3006篇
内科学   5790篇
皮肤病学   245篇
神经病学   1698篇
特种医学   442篇
外科学   3112篇
综合类   3799篇
现状与发展   2篇
一般理论   1篇
预防医学   6194篇
眼科学   203篇
药学   2398篇
  13篇
中国医学   148篇
肿瘤学   1183篇
  2024年   60篇
  2023年   607篇
  2022年   1303篇
  2021年   1637篇
  2020年   1468篇
  2019年   1170篇
  2018年   1197篇
  2017年   1173篇
  2016年   1329篇
  2015年   1204篇
  2014年   2684篇
  2013年   2473篇
  2012年   2075篇
  2011年   2241篇
  2010年   1602篇
  2009年   1413篇
  2008年   1308篇
  2007年   1231篇
  2006年   1003篇
  2005年   811篇
  2004年   604篇
  2003年   476篇
  2002年   384篇
  2001年   352篇
  2000年   273篇
  1999年   180篇
  1998年   132篇
  1997年   165篇
  1996年   103篇
  1995年   92篇
  1994年   79篇
  1993年   67篇
  1992年   64篇
  1991年   54篇
  1990年   45篇
  1989年   29篇
  1988年   32篇
  1987年   18篇
  1986年   10篇
  1985年   14篇
  1984年   10篇
  1983年   6篇
  1982年   6篇
  1981年   6篇
  1980年   2篇
  1979年   2篇
  1977年   4篇
  1976年   1篇
  1906年   1篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
中青年脑梗死68例临床分析   总被引:1,自引:0,他引:1  
脑梗死多见于老年人,但近年来中青年(16-45岁)患者逐渐增多且有年轻化趋势,深人探讨中青年脑梗死的致病因素及临床表现对其防治有重要意义。本文回顾性分析了我院自1998年1月到2004年12月问收治的中青年脑梗死患者68例,现报告如下。  相似文献   
52.
A cross-sectional, longitudinal study was undertaken on a group of acute non-A, non-B hepatitis patients, as well as on a control group of hepatitis B patients, in order to assess both the prevalence of the most important factors favoring infection, and the relevance of these factors in promoting evolution towards chronic liver disease. Exposures to unknown risk factors were present in 47.4% of acute non-A, non-B infections, followed by blood transfusions (17.9%), sporadic exposures (17.9%) and drug addiction (16.6%). Unknown as well as sporadic exposures showed a greater prevalence in control population if compared to non-A, non-B cases, while drug addiction was equally represented in the two groups, and blood transfusion nearly absent from control group. The risk of evolution to chronic liver disease was about 13 times greater in non-A, non-B group than in controls, with the greatest risk for drug addicts and the lowest for patients with unknown exposures. Among patients with known exposures, the lowest risk of chronic hepatitis was observed in post-transfusion and in sporadic cases, while the greatest was observed in drug addicts.Corresponding author.  相似文献   
53.
Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety.  相似文献   
54.
A woman's partner and the characteristics of their partnership can play an important role in the health of her pregnancy. Yet, with the notable exception of intimate partner violence, there has been little previous research addressing the associations between partner- or partnership-related factors and birth outcomes. This analysis tested the hypothesis that risk factors related specifically to partner or partnership characteristics increased the risk for preterm birth. Between 2003 and 2005, a total of 580 preterm cases (20–36 weeks gestational age at delivery) and 633 term controls (≥37 weeks) were selected from women delivering at an obstetric hospital in Lima, Peru. Each woman completed a confidential, structured interview and provided biological specimens within 48 h after delivery. Multivariable logistic regression was used to assess associations between partner and partnership characteristics and preterm birth. After adjustment for behavioral, demographic, and obstetric risk factors, ever having had a partner with a history of drug use (aOR = 1.91, 95% CI 1.22–2.99), ever having had anal sex (aOR = 1.40, 95% CI 1.07–1.84), having a current partner with a history of visiting prostitutes (aOR = 1.69, 95% CI 1.22–2.33), and perceiving one's current partner as a “womanizer” (aOR = 1.34, 95% CI 1.02–1.77) were significantly associated with an elevated risk of preterm birth when tested in separate models. These four factors were then used to create a composite partnership risk score, which showed an increasing dose-response relationship with preterm birth risk (per additional partner risk factor: aOR = 1.31, 95% CI 1.16–1.49). These results highlight the importance of considering a broader set of risk factors for preterm birth, specifically those related to a woman's partner and partnership characteristics. Further research could clarify the specific mechanisms through which these partner and partnership characteristics may increase the risk of preterm birth.  相似文献   
55.
The aim of this study was to assess risk behaviors and its association with caries activity and dental caries in Japanese children. The subjects were 392 young Japanese children who underwent dental health check-up at 18, 30 and 42 months of age. Oral examinations, Cariostat tests and dental health questionnaires were carried out at each time. The caries prevalence of children was 1.5% at 18 months, 9.9% at 30 months and 28.1% at 42 months. Caries activity based on the Cariostat scores of children was correlated with caries status (caries-free/carious) at 42 months. In children with caries during each examination period at 42 months, eating snacks while playing was ranked as the most important behavioral risk (P < 0.001), followed by breast-feeding (P < 0.01), non setting of time for snacks (P < 0.05) and frequency of snacks (P < 0.05) at 18 months old; non brushing by mother (P < 0.05) and eating snacks while playing (P < 0.05) were ranked highest at 30 months old. In addition, eating snacks while playing (P < 0.001) at 42 months old was the only a significant factor for children with caries. Caries activity and risk behaviors were associated with caries experience at different age periods of childhood.  相似文献   
56.
Population-based association studies are powerful tools for the genetic mapping of complex diseases. However, this method is sensitive to potential confounding by population structure. While statistical methods that use genetic markers to detect and control for population structure have been the focus of current literature, the utility of self-defined race/ethnicity in controlling for population structure has been controversial. In this study of 1334 individuals, who self-identified as either African American, European American or Hispanic, we demonstrated that when the true underlying genetic structure and the self-defined racial/ethnic groups were roughly in agreement with each other, the self-defined race/ethnicity information was useful in the control of population structure.  相似文献   
57.
目的探讨群体损伤院前急救转运存在的风险与防范对策。方法通过547例群体损伤转运,分析影响安全转运存在的风险,正确评估和判断风险,制定有效的防范措施和对策。结果 547例伤员安全转运入院治疗,入院率100%。结论预见转运存在风险,采取有效防范对策,是确保成功转运的关键因素。  相似文献   
58.
目的 对比分析食管癌病例组与对照组血缘亲属食管癌患病风险,并了解食管癌家族中危险亲属人群患病的新线索.方法 采用病例对照研究方法 ,对食管癌病例组及对照组各720例进行逐层分析,以比较两组各血缘亲属父系、母系食管癌患病危险度(OR)的大小及差异.结果 (1)病例组Ⅰ级亲属食管癌患病危险度(1.34%~2.24%)显著高于对照组(0.78%~1.21%)(P<0.01);Ⅰ级亲属中病例组父母亲食管癌患病危险度为6.11%,显著高于对照组父母亲食管癌患病危险度2.97%(P<0O01).(2)以血缘亲属中父系和母系亲属逐层分析可见,病例组父系食管癌患病危险度(0.87%~1.01%)与母系患病危险度(0.50%~0.79%)均显著高于对照组父系食管癌患病危险度(0.53%~0.65%)与母系患病危险度(0.38%~0.47%)(P<0.05).进一步分析显示,病例组父系中男性亲属与母系中女性亲属,即父系中祖父、父亲、叔伯食管癌患病危险度为2.68%与母系中外祖母、母亲、姨的食管癌患病危险度1.91%均显著高于对照组父系中男性亲属食管癌患病危险度1.50%与母系中女性亲属食管癌患病危险度0.92%(P<0.01).结论 山西省食管癌患者血缘亲属发病危险主要是父亲及其兄弟、母亲及其姐妹,其下代患食管癌风险要大.  相似文献   
59.
眼底动脉硬化与血压、血糖、血脂的多元分析与评估   总被引:1,自引:0,他引:1  
目的探讨眼底动脉硬化与血压、血脂、血糖的相关性,评估中风危险度。方法对2004年5月至2008年10月就诊的患者335例,作为观察组,并与无症状的健康体检者180例作对照,动态检测眼底动脉硬化、血压、血糖、血脂的异常变化,并做综合量化评估。结果脑血管疾病与眼底动脉硬化、血压、血糖、血脂等因素密切相关。结论眼底动脉硬化、血糖、血脂、血压异常的量化评分,能够预估中风,以便采取预防性治疗。  相似文献   
60.
出血性脑梗死危险因素的Logistic回归分析   总被引:4,自引:3,他引:1  
目的探讨出血性脑梗死的危险因素。方法根据专业知识确定与出血性脑梗死有关的因素,采用非条件Logistic回归确定危险因素。结果大面积梗死灶、使用抗凝剂或溶栓治疗、糖尿病史是出血性脑梗死的独立危险因素,与年龄、高血压史、高血脂关系不大。结论大面积脑梗死、使用抗凝剂或溶栓、糖尿病患者发生梗死后出血的几率增大,及时行影像学检查可以早期发现。  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