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   330616篇
  免费   11585篇
  国内免费   1212篇
耳鼻咽喉   3337篇
儿科学   9518篇
妇产科学   6684篇
基础医学   39950篇
口腔科学   4846篇
临床医学   27176篇
内科学   60589篇
皮肤病学   4975篇
神经病学   28103篇
特种医学   16613篇
外科学   49767篇
综合类   4425篇
现状与发展   5篇
一般理论   81篇
预防医学   27376篇
眼科学   6960篇
药学   22272篇
中国医学   2218篇
肿瘤学   28518篇
  2023年   985篇
  2022年   2739篇
  2021年   4824篇
  2020年   2467篇
  2019年   3593篇
  2018年   25703篇
  2017年   20101篇
  2016年   23113篇
  2015年   6470篇
  2014年   7651篇
  2013年   9059篇
  2012年   19316篇
  2011年   32618篇
  2010年   25475篇
  2009年   17190篇
  2008年   28156篇
  2007年   30157篇
  2006年   8818篇
  2005年   10032篇
  2004年   10373篇
  2003年   10407篇
  2002年   7768篇
  2001年   4626篇
  2000年   4416篇
  1999年   3411篇
  1998年   1499篇
  1997年   1184篇
  1996年   1031篇
  1995年   956篇
  1994年   842篇
  1993年   697篇
  1992年   1606篇
  1991年   1648篇
  1990年   1473篇
  1989年   1309篇
  1988年   1204篇
  1987年   1067篇
  1986年   1031篇
  1985年   910篇
  1984年   662篇
  1983年   583篇
  1982年   423篇
  1981年   377篇
  1980年   377篇
  1979年   521篇
  1978年   414篇
  1977年   391篇
  1976年   350篇
  1974年   377篇
  1973年   328篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
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   
102.
103.
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   
104.
105.
106.
107.
ABSTRACT

Tryptophan (Trp) is not only a nutrient enhancer but also has systemic effects. Trp metabolites signaling through the well-known aryl hydrocarbon receptor (AhR) constitute the interface of microbiome-gut-brain axis. However, the pathway through which Trp metabolites affect central nervous system (CNS) function have not been fully elucidated. AhR participates in a broad variety of physiological and pathological processes that also highly relevant to intestinal homeostasis and CNS diseases. Via the AhR-dependent mechanism, Trp metabolites connect bidirectional signaling between the gut microbiome and the brain, mediated via immune, metabolic, and neural (vagal) signaling mechanisms, with downstream effects on behavior and CNS function. These findings shed light on the complex Trp regulation of microbiome-gut-brain axis and add another facet to our understanding that dietary Trp is expected to be a promising noninvasive approach for alleviating systemic diseases.  相似文献   
108.
109.
110.
Background. It has been reported that gender differences in cardiovascular outcomes found in adults also are present in children who undergo surgical repair for congenital heart disease. Methods. California statewide hospital discharge data 1989–99 were used to study outcomes in children <18 years undergoing cardiac surgery. Hospital discharge data were linked to death registry data to study postdischarge death within 30 days of discharge. We used logistic regression to evaluate the effect of gender on mortality controlling for age, race and ethnicity, type of insurance, household income, date and month of surgery, type of admission, hospital case volume, and various types of procedures. Results. There were 25 402 cardiac surgery cases with 1505 in‐hospital deaths (mortality rate of 5.92%). An additional 37 deaths occurred within 30 days after hospital discharge. Crude mortality rates for males (5.99%) and females (5.84%) were not significantly different. However, fewer neonates were female and females underwent a higher proportion of low‐risk procedures than males. Logistic regression revealed that females, compared with males, had a significantly higher odds ratio (OR) for in‐hospital mortality (OR = 1.18, P < .01) and overall (up to 30 days post discharge) mortality (OR = 1.18, P < .01). The risk‐adjusted length of hospital stay was similar between females and males while charges per hospital day were slightly higher in females than males. The prevalence of Down syndrome, pulmonary hypertension, and failure to thrive were higher in females. Conclusions. Female gender is associated with an 18% higher in‐hospital and 30‐day postdischarge mortality as compared with male gender. There was no difference in length of hospital stay between males and females. The mechanism by which female gender acts as a risk factor requires further investigation.  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