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   605篇
  免费   57篇
  国内免费   2篇
耳鼻咽喉   33篇
儿科学   31篇
妇产科学   13篇
基础医学   86篇
口腔科学   22篇
临床医学   47篇
内科学   82篇
皮肤病学   5篇
神经病学   43篇
特种医学   75篇
外科学   85篇
综合类   5篇
一般理论   5篇
预防医学   31篇
眼科学   2篇
药学   22篇
肿瘤学   77篇
  2023年   4篇
  2021年   9篇
  2020年   9篇
  2019年   10篇
  2018年   16篇
  2017年   5篇
  2016年   16篇
  2015年   14篇
  2014年   23篇
  2013年   20篇
  2012年   38篇
  2011年   30篇
  2010年   10篇
  2009年   13篇
  2008年   30篇
  2007年   25篇
  2006年   32篇
  2005年   24篇
  2004年   27篇
  2003年   27篇
  2002年   23篇
  2001年   19篇
  2000年   21篇
  1999年   19篇
  1998年   9篇
  1996年   4篇
  1995年   5篇
  1994年   7篇
  1993年   4篇
  1992年   21篇
  1991年   12篇
  1990年   9篇
  1989年   16篇
  1988年   10篇
  1987年   4篇
  1986年   7篇
  1985年   7篇
  1984年   5篇
  1980年   3篇
  1979年   3篇
  1977年   5篇
  1976年   7篇
  1974年   3篇
  1970年   5篇
  1937年   8篇
  1936年   11篇
  1932年   3篇
  1930年   3篇
  1929年   2篇
  1927年   3篇
排序方式: 共有664条查询结果,搜索用时 15 毫秒
1.
The coronavirus disease 2019 pandemic and the consequent global lockdown posed a particular challenge for youths with mental health problems. Crucial interference with their everyday lives likely increased psychological distress while accessibility of conventional mental health care was limited. Ongoing online trials offer a unique opportunity to analyse mental health status and help-seeking behaviour of adolescents during the pandemic. The ProHEAD-online trial aims at improving help-seeking behaviour of children and adolescents with significant psychological impairment. From January to May 2020, 1,042 students had access to the ProHEAD-online platform providing information on mental illness, monitoring, peer support and professional counselling. In the week from 11 March, when schools were closed in Germany, a drastic (more than 2 standard deviations) but time-limited increase in utilization of the ProHEAD-online services became apparent. This may indicate a worsened mental health status and an increased help seeking via digital services during the lockdown. Although this finding is purely observational, it speaks to the importance of evidence-based online service in the field of mental health within the current crisis and beyond.  相似文献   
2.
3.
4.
Journal of Neuro-Oncology - The prognostic impact of the histopathologic features of recurrent glioblastoma surgical specimens is unknown. We sought to determine whether key histopathologic...  相似文献   
5.
Past public health crises (e.g., tobacco, alcohol, opioids, cholera, human immunodeficiency virus (HIV), lead, pollution, venereal disease, even coronavirus (COVID-19) have been met with interventions targeted both at the individual and all of society. While the healthcare community is very aware that the global pandemic of non-communicable diseases (NCDs) has its origins in our Western ultraprocessed food diet, society has been slow to initiate any interventions other than public education, which has been ineffective, in part due to food industry interference. This article provides the rationale for such public health interventions, by compiling the evidence that added sugar, and by proxy the ultraprocessed food category, meets the four criteria set by the public health community as necessary and sufficient for regulation—abuse, toxicity, ubiquity, and externalities (How does your consumption affect me?). To their credit, some countries have recently heeded this science and have instituted sugar taxation policies to help ameliorate NCDs within their borders. This article also supplies scientific counters to food industry talking points, and sample intervention strategies, in order to guide both scientists and policy makers in instituting further appropriate public health measures to quell this pandemic.  相似文献   
6.
The publication of recent randomized trials has prompted a significant shift in both our understanding and the management of patients with melanoma. Here, the current management of the regional lymph nodes in patients with melanoma is discussed. This review focuses on selection for sentinel lymph node biopsy, management of the positive sentinel node, management of the clinically positive node, and the controversy over the therapeutic value of early nodal intervention.  相似文献   
7.
ObjectiveThe role of school closure in mitigating coronavirus disease 2019 (COVID-19) transmission has been questioned. In our medical centre, during a 9-week national lockdown, an alternative school was opened for health-care workers' (HCW) children with a small number of children per class and strict symptom surveillance. After lockdown was lifted we screened children and their parents for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology.MethodsWe conducted a cross-sectional study of HCW parents and their children after one teacher contracted COVID-19 following exposure at home and 53 children were exposed, isolated and tested by RT-PCR. We compared families with children attending the alternative school with families whose children who remained at home during the 9-week lockdown. Epidemiological and medical data were collected using a short questionnaire; nasopharyngeal and oropharyngeal swabs were obtained and tested for SARS-CoV-2 by RT-PCR, and blood was collected for SARS-CoV-2 IgA and IgG titres.ResultsA total of 435 children attended the Sheba alternative school. Among the 53 children exposed to the infected teacher, none tested positive by RT-PCR. Of these, 18 children–parent pairs were tested for serology and all were negative. A total of 106/435 (24%) children and their 78 parents were recruited for the cross-sectional study; 70 attended the Sheba school and 36 did not. Approximately 16% of children in either group reported symptoms (11/70 in the school group and 6/36 in the ‘stay home’ group), but SARS-CoV-2 was not detected by PCR in any, and previous exposure, as determined by serological tests, was low and not significantly different between the groups.ConclusionIn an alternative school for children of HCWs, active during COVID-19 national outbreak, we found no evidence of increased infection compared with children that stayed home.  相似文献   
8.
Effective treatment of the cognitive symptoms of schizophrenia has remained an elusive goal. Despite the intense focus on treatments acting at or via cholinergic mechanisms, little remains known about the dynamic cholinergic abnormalities that contribute to the manifestation of the cognitive symptoms in patients. Evidence from basic neuroscientific and psychopharmacological investigations assists in proposing detailed cholinergic mechanisms and treatment targets for enhancement of attentional performance. Dynamic, cognitive performance-dependent abnormalities in cholinergic activity have been observed in animal models of the disorder and serve to further refine such proposals. Finally, the potential usefulness of individual groups of cholinergic drugs and important issues concerning the interactions between pro-cholinergic and antipsychotic treatments are addressed. The limited evidence available from patient studies and animal models indicates pressing research needs in order to guide the development of cholinergic treatments of the cognitive symptoms of schizophrenia.  相似文献   
9.
10.

Background

Delays in the release of national vital statistics hinder timely assessment of influenza severity, especially during pandemics. Inpatient mortality records could provide timelier estimates of influenza‐associated mortality.

Methods

We compiled weekly age‐specific deaths for various causes from US State Inpatient Databases (1990–2010) and national vital statistics (1990–2009). We calculated influenza‐attributable excess deaths by season based on Poisson regression models driven by indicators of respiratory virus activity, seasonality, and temporal trends.

Results

Extrapolations of excess mortality from inpatient data fell within 11% and 17% of vital statistics estimates for pandemic and seasonal influenza, respectively, with high year‐to‐year correlation (Spearman''s rho = 0·87–0·90, P < 0·001, n = 19). We attribute 14 800 excess respiratory and cardiac deaths (95% CI: 10 000–19 650) to pandemic influenza activity during April 2009–April 2010, 79% of which occurred in people under 65 years.

Conclusions

Modeling inpatient mortality records provides useful estimates of influenza severity in advance of national vital statistics release, capturing both the magnitude and the age distribution of pandemic and epidemic deaths. We provide the first age‐ and cause‐specific estimates of the 2009 pandemic mortality burden using traditional ‘excess mortality’ methods, confirming the unusual burden of this virus in young populations. Our inpatient‐based approach could help monitor mortality trends in other infectious diseases.  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