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   3780篇
  免费   261篇
  国内免费   2篇
耳鼻咽喉   29篇
儿科学   111篇
妇产科学   91篇
基础医学   450篇
口腔科学   32篇
临床医学   522篇
内科学   810篇
皮肤病学   36篇
神经病学   373篇
特种医学   77篇
外科学   316篇
综合类   62篇
一般理论   5篇
预防医学   527篇
眼科学   149篇
药学   242篇
中国医学   2篇
肿瘤学   209篇
  2023年   33篇
  2022年   45篇
  2021年   105篇
  2020年   95篇
  2019年   121篇
  2018年   113篇
  2017年   100篇
  2016年   107篇
  2015年   87篇
  2014年   133篇
  2013年   194篇
  2012年   302篇
  2011年   286篇
  2010年   138篇
  2009年   132篇
  2008年   269篇
  2007年   252篇
  2006年   237篇
  2005年   230篇
  2004年   240篇
  2003年   216篇
  2002年   189篇
  2001年   28篇
  2000年   14篇
  1999年   33篇
  1998年   41篇
  1997年   31篇
  1996年   27篇
  1995年   13篇
  1994年   25篇
  1993年   17篇
  1992年   17篇
  1991年   24篇
  1990年   18篇
  1989年   7篇
  1988年   12篇
  1987年   4篇
  1986年   6篇
  1985年   8篇
  1984年   5篇
  1983年   8篇
  1982年   9篇
  1980年   8篇
  1978年   6篇
  1977年   9篇
  1976年   4篇
  1975年   6篇
  1974年   9篇
  1973年   6篇
  1972年   4篇
排序方式: 共有4043条查询结果,搜索用时 343 毫秒
61.
62.
Outcomes following healthcare transition (HCT) from pediatric to adult HIV care are not well described. We sought to describe clinical outcomes following HCT within our institution among young adults with behavioral-acquired (N?=?31) and perinatally-acquired (N?=?19) HIV. We conducted a retrospective cohort study among HIV-infected adults who attempted transition from pediatric to adult HIV care within our institution. The primary end point was retention in care, defined as the completion of at least two visits over 12 months following linkage to adult care. Additional end points include time to linkage to adult care, and changes in CD4?+?T cell count and HIV RNA across time. Outcomes were compared between perinatal and behavioral HIV cohorts. Binary data were analyzed using the Fisher exact test and continuous data were analyzed using the Mann–Whitney test. Forty-three (86%) of 50 patients were successfully linked to adult care. The median time to linkage was 98 days. Fifty percent of patients achieved full retention in care at 12 months post-linkage. Though those with behavioral-acquired HIV attempted transfer at an older age, the groups did not differ in rates of linkage and retention in adult care. CD4?+?T cell counts and rates of viral suppression did not differ between pre- and post-HCT periods. Despite high rates of successful linkage to adult care in our study population, rates of retention in adult HIV care following HCT were low. These results imply that challenges remain in the adult HIV care setting toward improving the HCT process.  相似文献   
63.
64.
65.
We conducted a weight-of-evidence (WoE) analysis to assess whether the current body of research supports a causal relationship between long-term ozone exposure (defined by EPA as at least 30 days in duration) at ambient levels and cardiovascular (CV) effects. We used a novel WoE framework based on the United States Environmental Protection Agency's National Ambient Air Quality Standards causal framework for this analysis. Specifically, we critically evaluated and integrated the relevant epidemiology and experimental animal data and classified a causal determination based on categories proposed by the Institute of Medicine's 2008 report, Improving the Presumptive Disability Decision-making Process for Veterans. We found that the risks of CV effects are largely null across human and experimental animal studies. The few positive associations reported in studies of CV morbidity and mortality are very small in magnitude, mainly reported in single-pollutant models, and likely attributable to bias, chance, or confounding. The few positive effects in experimental animal studies were observed mainly in ex vivo studies at high exposures, and even the in vivo findings are not likely relevant to humans. The available data also do not support a biologically plausible mechanism for the effects of ozone on the CV system. Overall, the current WoE provides no convincing case for a causal relationship between long-term exposure to ambient ozone and adverse effects on the CV system in humans, but the limitations of the available studies preclude definitive conclusions regarding a lack of causation; thus, we categorize the strength of evidence for a causal relationship between long-term exposure to ozone and CV effects as “below equipoise.”  相似文献   
66.
67.
While research has identified gender differences in characteristics and outcomes of smokers in the general population, no studies have examined this among smokers with psychosis. This study aimed to explore gender differences among 298 smokers with psychosis (schizophrenia, schizoaffective and bipolar affective disorder) participating in a smoking intervention study. Results revealed a general lack of gender differences on a range of variables for smokers with psychosis including reasons for smoking/quitting, readiness and motivation to quit, use of nicotine replacement therapy, and smoking outcomes including point prevalence or continuous abstinence, and there were no significant predictors of smoking reduction status according to gender at any of the follow-up time-points. The current study did find that female smokers with psychosis were significantly more likely than males to report that they smoked to prevent weight gain. Furthermore, the females reported significantly more reasons for quitting smoking and were more likely to be driven by extrinsic motivators to quit such as immediate reinforcement and social influence, compared to the male smokers with psychosis. Clinical implications include specifically focussing on weight issues and enhancing intrinsic motivation to quit smoking for female smokers with psychosis; and strengthening reasons for quitting among males with psychosis.  相似文献   
68.
69.
70.
BACKGROUND: Despite an unprecedented demand for gastroenterology services, the number of gastroenterology trainees has decreased over 50% since 1993. Women comprise nearly 50% of the U.S. medical school student population; yet only occupy 16% of gastroenterology fellowship positions. In order to recruit the best candidates to gastroenterology we must be able to demonstrate the attractiveness of a career in the field. A prospective study was performed to identify the career choices of graduates from gastroenterology fellowship programs using a prospective study model and to identify whether gender differences exist in the practice of gastroenterologists up to 5 yr after completion of training. METHODS: A survey gathering information on demographics, practice pattern, and income was mailed to two cohorts of gastroenterology fellows 3 and 5 yr after graduation. RESULTS: A total of 247 subjects completed the 3 yr and 220 subjects responded to the 5-yr survey. At 3 yr, men reported higher income (p < 0.001), worked longer hours per week (p < 0.002), and were more likely to be part owner of the practice (p= 0.027). Females reported fewer children (p < 0.007), lower board certification rates (p < 0. 002), worked for larger, multispecialty practices (p < 0.001), and practiced more internal medicine. These differences were still present at 5 yr into gastroenterology practice. CONCLUSIONS: Significant differences in practice type, earnings, board certification, professional standing, and alterations in family planning are noted between male and female gastroenterologists in the initial 5 yr of their practice.  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