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   49115篇
  免费   3742篇
  国内免费   111篇
耳鼻咽喉   468篇
儿科学   1836篇
妇产科学   1304篇
基础医学   6125篇
口腔科学   432篇
临床医学   6270篇
内科学   8878篇
皮肤病学   999篇
神经病学   4988篇
特种医学   960篇
外科学   5138篇
综合类   397篇
现状与发展   1篇
一般理论   86篇
预防医学   6938篇
眼科学   845篇
药学   3428篇
中国医学   60篇
肿瘤学   3815篇
  2024年   57篇
  2023年   512篇
  2022年   815篇
  2021年   1816篇
  2020年   1104篇
  2019年   1793篇
  2018年   1896篇
  2017年   1459篇
  2016年   1549篇
  2015年   1627篇
  2014年   2289篇
  2013年   2991篇
  2012年   4483篇
  2011年   4408篇
  2010年   2408篇
  2009年   1990篇
  2008年   3455篇
  2007年   3393篇
  2006年   3158篇
  2005年   2957篇
  2004年   2554篇
  2003年   2138篇
  2002年   1862篇
  2001年   210篇
  2000年   137篇
  1999年   216篇
  1998年   303篇
  1997年   216篇
  1996年   176篇
  1995年   155篇
  1994年   115篇
  1993年   98篇
  1992年   66篇
  1991年   48篇
  1990年   47篇
  1989年   50篇
  1988年   34篇
  1987年   26篇
  1986年   29篇
  1985年   25篇
  1984年   37篇
  1983年   38篇
  1982年   16篇
  1981年   20篇
  1980年   21篇
  1978年   20篇
  1977年   15篇
  1976年   14篇
  1975年   16篇
  1973年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Background: Smoking is considered to be a risk factor for patients undergoing surgery and anesthesia, but it is unclear whether this is applicable to patients undergoing ambulatory surgery. The aim of this study was to determine the risk of respiratory complications and wound infection among smokers.

Methods: The authors studied a random selection of 489 adult patients undergoing ambulatory surgery. Smoking status was determined by self-report and confirmed with end-expired carbon monoxide analysis. The risk of respiratory complications (i.e., desaturation, cough, laryngospasm, bronchospasm, breath-holding, or apnea) and wound infection (i.e., wound redness or discharge +/- positive microbial culture, requiring antibiotic therapy) in smokers versus nonsmokers was ascertained. Odds ratios were estimated from multivariable logistic regression and adjusted for age, gender, body mass index, partner's smoking status, domiciliary smoking exposure, and extent and duration of surgery.

Results: Most smokers continued to smoke up until the day of surgery. Smokers had a higher rate of respiratory complications (32.8%vs. 25.9%; adjusted odds ratio, 1.71; 95% confidence interval, 1.03-2.84;P = 0.038) and wound infection (3.6%vs. 0.6%; odds ratio, 16.3; 95% confidence interval, 1.58-175;P = 0.019). Odds ratios comparing current plus ex-smokers with nonsmokers were of similar magnitude for most of these complications.  相似文献   

62.
63.
64.
65.
66.
Unfortunately, acute pulmonary embolism is still a far too common occurrence. Fortunately, with prompt recognition, diagnosis, and treatment, mortality can be reduced. This article provides an overview of risk factors, diagnostic studies, and treatment of patients with acute pulmonary embolism in the critical care setting.  相似文献   
67.
Shape and letter cancellation test performance was investigated among large samples of African American, Hispanic, and White non-demented elders. Ethnic minority elders took significantly longer to complete both tasks compared to Whites. An index of task efficiency, which simultaneously measures time and accuracy, suggested that slower time by minority elders was not related to a measurable effort to achieve greater accuracy. The frequency of commission errors was greater in our sample than in previous reports, especially among ethnic minority elders. Although significant differences were observed between the ethnic groups when matched for years of education, equating for literacy level eliminated all performance differences between African Americans and Whites on both cancellation tasks.  相似文献   
68.
69.
To increase preschoolers' science and mathematics learning experiences both within and outside the classroom, we developed age-appropriate materials containing general questions and instructions that teachers and parents could use when interacting with their students and children. The questions and instructions were related to a specific science or mathematics skill (e.g., classifying), but were general enough so that they could be applied to a variety of situations. Observations of three classrooms and interviews with the classroom teachers and aides, and the parents of the children in the classrooms suggested that use of these materials was beneficial to the children, teachers, and parents, and resulted in increasing the amount of science and mathematics activities and discussions in two of the classrooms as well as outside the classrooms.  相似文献   
70.
BACKGROUND: Abnormalities in the limbic-hypothalamic-pituitary-adrenal (LHPA) axis have been implicated in the pathogenesis of obsessive-compulsive disorder (OCD). To our knowledge, however, no prior study has measured pituitary gland volume in OCD. METHODS: Volumetric magnetic resonance imaging studies were conducted in 31 psychotropic drug-na?ve children (10 boys, 21 girls) aged 8-17 years and 31 case-matched healthy comparison subjects. RESULTS: Pituitary volume was significantly smaller in patients with OCD as compared with healthy control subjects (11% smaller). Smaller pituitary volume in patients with OCD was associated with increased compulsive but not obsessive symptom severity. Boys with OCD had smaller pituitary gland volumes compared with control boys (20% smaller). No significant differences in pituitary volume were observed between girls with OCD and control girls. Boys with OCD had significantly smaller pituitary volumes than girls with OCD (31% smaller), whereas control boys also had smaller pituitary gland volumes compared with control girls (21% smaller). CONCLUSIONS: These findings provide new evidence of reduced pituitary volume in pediatric OCD that seems to be more prominent in male patients. The observed alterations in pituitary volume are consistent with neuroendocrine studies that have reported abnormalities in the LHPA axis in OCD.  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