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   189971篇
  免费   13115篇
  国内免费   2190篇
耳鼻咽喉   2677篇
儿科学   3452篇
妇产科学   4143篇
基础医学   28300篇
口腔科学   3905篇
临床医学   18449篇
内科学   35035篇
皮肤病学   5186篇
神经病学   14089篇
特种医学   9555篇
外国民族医学   5篇
外科学   25482篇
综合类   4619篇
现状与发展   12篇
一般理论   93篇
预防医学   11279篇
眼科学   5187篇
药学   16551篇
  15篇
中国医学   2552篇
肿瘤学   14690篇
  2023年   1078篇
  2022年   2919篇
  2021年   6234篇
  2020年   3279篇
  2019年   4479篇
  2018年   5431篇
  2017年   4097篇
  2016年   5198篇
  2015年   7064篇
  2014年   8596篇
  2013年   10221篇
  2012年   15236篇
  2011年   14870篇
  2010年   8850篇
  2009年   7390篇
  2008年   11013篇
  2007年   10739篇
  2006年   9893篇
  2005年   9374篇
  2004年   8216篇
  2003年   7128篇
  2002年   6175篇
  2001年   4943篇
  2000年   4616篇
  1999年   3766篇
  1998年   1554篇
  1997年   1188篇
  1996年   1109篇
  1995年   1015篇
  1994年   888篇
  1993年   747篇
  1992年   1727篇
  1991年   1741篇
  1990年   1485篇
  1989年   1337篇
  1988年   1248篇
  1987年   1109篇
  1986年   1083篇
  1985年   930篇
  1984年   686篇
  1983年   598篇
  1982年   431篇
  1981年   401篇
  1980年   360篇
  1979年   549篇
  1978年   424篇
  1977年   404篇
  1976年   356篇
  1974年   377篇
  1973年   340篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
Urinary iodine concentrations (UICs) in the US have been reported to be stable since 1988–1994, although those in selected subgroups remained low. We aimed to investigate iodine status among adults (≥20 years) by two different criteria of assessing iodine deficiency in population. Utilizing National Health and Nutrition Examination Surveys 2001–2012, we conducted linear logistic regressions adjusting for covariates. The prevalence of <50?μg/L UIC was higher in women than in men; increased from 11.6% (2001–2004) to 13.2% (2009–2012) at the national level and in young adults, non-Hispanic blacks (NHBs) and non-users of iodine-containing supplements (all, p?<0.05); the adjusted odds ratios (95%CI) in young adults (1.54 [1.11–2.15], =?0.0007) and NHBs (1.70 [1.15–2.52], =?0.0078). Median UICs confirm women and NHBs being in borderline iodine status. Recognizing the critical consequence of iodine deficiency particularly in women and NHBs, regular monitoring of iodine status is important for public health in the US.  相似文献   
104.
105.
Previous epidemiologic studies have assessed the role of the exposure to ambient air pollution in the development of cardiac birth defects, but they have provided somewhat inconsistent results. To assess the associations between exposure to ambient air pollutants and the risk of cardiac defects, a population-based case-control study was conducted using 1087 cases of cardiac defects and a random sample of 10,870 controls from 1,533,748 Taiwanese newborns in 2001 to 2007.Logistic regression was performed to calculate odds ratios for 10 ppb increases in O3 and 10 μg/m3 increases in PM10. In addition, we compared the risk of cardiac defects in 4 categories-high exposure (>75th percentile); medium exposure (75th to 50th percentile); low exposure (<50th–25th percentile); reference (<25th percentile) based on the distribution of each pollutant. The risks of ventricular septal defects (VSD), atrial septal defects (ASD), and patent ductus arteriosus (PDA) were associated with 10 ppb increases in O3 exposure during the first 3 gestational months among term and preterm babies. In comparison between high PM10 exposure and reference category, there were statistically significant elevations in the effect estimates of ASD for all and terms births. In addition, there was a negative or weak association between SO2, NO2, CO, and cardiac defects.The study proved that exposure to outdoor air O3 and PM10 during the first trimester of gestation may increase the risk of VSD, ASD, and PDA.  相似文献   
106.
107.
Abstract

Purpose: We examined underlying psychosocial processes of a behavioral treatment for urinary incontinence (UI) of prostate cancer survivors.

Design: Secondary analysis of data collected from a clinical trial.

Sample: Two hundred forty-four prostate cancer survivors who participated in a clinical trial of behavioral intervention to UI as intervention or control subjects.

Methods: The participants had a 3-month behavioral intervention or usual care and were followed up for an additional 3?months. They were assessed at baseline, 3, and 6?months. Latent growth curve models were performed to examine trajectories of each study variable and relationships among the variables.

Findings: Increasing self-efficacy and social support were significantly and independently associated with more reduction of urinary leakage frequency over time.

Implications for psychosocial oncology: Providing problem-solving skills and social support, including peer support, are essential for empowering patients to reduce UI.  相似文献   
108.
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