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   2578篇
  免费   161篇
  国内免费   17篇
耳鼻咽喉   26篇
儿科学   45篇
妇产科学   80篇
基础医学   246篇
口腔科学   58篇
临床医学   314篇
内科学   421篇
皮肤病学   22篇
神经病学   152篇
特种医学   196篇
外科学   345篇
综合类   63篇
一般理论   4篇
预防医学   352篇
眼科学   125篇
药学   148篇
肿瘤学   159篇
  2021年   48篇
  2020年   17篇
  2019年   45篇
  2018年   47篇
  2017年   30篇
  2016年   30篇
  2015年   45篇
  2014年   61篇
  2013年   84篇
  2012年   86篇
  2011年   111篇
  2010年   82篇
  2009年   81篇
  2008年   103篇
  2007年   98篇
  2006年   105篇
  2005年   89篇
  2004年   77篇
  2003年   76篇
  2002年   89篇
  2001年   59篇
  2000年   78篇
  1999年   74篇
  1998年   37篇
  1997年   38篇
  1996年   40篇
  1995年   32篇
  1994年   25篇
  1993年   22篇
  1992年   45篇
  1991年   46篇
  1990年   47篇
  1989年   44篇
  1988年   35篇
  1987年   37篇
  1986年   37篇
  1985年   37篇
  1984年   40篇
  1983年   71篇
  1982年   64篇
  1981年   57篇
  1980年   63篇
  1979年   37篇
  1978年   36篇
  1977年   38篇
  1976年   25篇
  1974年   22篇
  1973年   18篇
  1970年   15篇
  1966年   22篇
排序方式: 共有2756条查询结果,搜索用时 15 毫秒
21.
22.
Ligation of a hemodynamically significant ductus arteriosus results in significant changes in loading conditions which have predictable consequences. Postligation cardiac syndrome, defined as hypotension requiring inotropic support and failure of oxygenation and ventilation, may occur 6‐12 hours following ligation due to left ventricular systolic and diastolic failure, respectively. Afterload is the primary driver of this decompensation. In this review, we describe the pathophysiological changes in loading conditions associated with postligation cardiac syndrome and other contributors to cardiovascular dysfunction following ductal ligation. We present strategies for perioperative optimization and a physiology‐based algorithm for postoperative management guided by targeted neonatal echocardiography. The use of these strategies to reduce the frequency of postligation deterioration may be an avenue to improve outcomes for neonates in this vulnerable patient population.  相似文献   
23.
Use of Resuscitative endovascular balloon occlusion of the aorta (REBOA) for control of non-compressible hemorrhage is a re-emerging technology that historically is employed by surgeons. We present a case in which REBOA was successfully placed by an emergency physician in a critical mass casualty patient awaiting transfer to the operating table. This case is an example in which emergency physicians, in collaboration with the surgeon, can utilize REBOA to temporize non-compressible hemorrhage when a surgeon is not immediately available.  相似文献   
24.
Agency leaders and therapists are essential stakeholders in implementation of evidence-based practices (EBPs) within publicly-funded mental health services. Little is known about how these stakeholders differ in their perceptions of specific EBPs and which individual and organizational factors differentially influence these perceptions. Within the context of a system-driven implementation of multiple EBPs, survey data from 160 leaders and 720 therapists were examined to assess differences in perceptions of six EBPs. Findings indicated that leaders and therapists have unique perspectives and preferences regarding EBPs that are shaped by distinct sociodemographic and professional characteristics and aspects of organizational functioning.  相似文献   
25.
26.
27.
Background: Longitudinal studies of substance users report difficulty in locating and completing 12‐month interviews, which may compromise study validity. Objectives: This study examined rates and predictors of contact difficulty and in‐person follow‐up completion among patients presenting with cocaine‐related chest pain to an inner‐city emergency department (ED). The authors hypothesize that less staff effort in contacting patients and lower follow‐up rates would bias subsequent substance use analysis by missing those with heavier substance misuse. Methods: A total of 219 patients aged 19 to 60 years (65% males; 78% African American) with cocaine‐related chest pain were interviewed in the ED and then in person at 3, 6, and 12 months. Demographics, substance use measures, and amount/type of research staff contacts (telephone, letters, home visits, and locating patient during return ED visits) were recorded. Poisson and negative binomial regression analyses were conducted to predict quantity of patient contacts for the 12‐month follow‐up. Results: Interview completion rates at 3, 6, and 12 months were 78, 82, and 80%, respectively. Average contact attempts to obtain each interview were 10 at 3 months (range 3–44), 8 at 6 months (1–31), and 8 at 12 months (1–49); 13% of patients required a home visit to complete the 12‐month interview. Participants requiring more contact attempts by staff were younger and reported more frequent binge drinking at baseline (p < 0.05), but were less likely to meet criteria for substance abuse or dependence (p < 0.5), or to report prior mental health treatment (p < 0.05). Comparisons of parallel regressions predicting contact difficulty based on the entire sample, the low‐effort group, and the difficult‐to‐reach group showed variation in findings. Conclusions: This study demonstrates that substantial staff effort is required to achieve adequate retention over 12 months of patients with substance misuse. Without these extensive efforts at follow‐up, longitudinal analyses may be biased.  相似文献   
28.
29.
People tend to display the left cheek when posing for a portrait; however, this effect does not appear to generalise to advertising. The amount of body visible in the image and the sex of the poser might also contribute to the posing bias. Portraits also exhibit lateral lighting biases, with most images being lit from the left. This effect might also be present in advertisements. A total of 2801 full-page advertisements were sampled and coded for posing direction, lighting direction, sex of model, and amount of body showing. Images of females showed an overall leftward posing bias, but the biases in males depended on the amount of body visible. Males demonstrated rightward posing biases for head-only images. Overall, images tended to be lit from the top left corner. The two factors of posing and lighting biases appear to influence one another. Leftward-lit images had more leftward poses than rightward, while the opposite occurred for rightward-lit images. Collectively, these results demonstrate that the posing biases in advertisements are dependent on the amount of body showing in the image, and that biases in lighting direction interact with these posing biases.  相似文献   
30.
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