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   7204篇
  免费   526篇
  国内免费   12篇
耳鼻咽喉   107篇
儿科学   198篇
妇产科学   290篇
基础医学   925篇
口腔科学   81篇
临床医学   811篇
内科学   1363篇
皮肤病学   108篇
神经病学   706篇
特种医学   138篇
外科学   903篇
综合类   79篇
一般理论   16篇
预防医学   824篇
眼科学   189篇
药学   551篇
中国医学   5篇
肿瘤学   448篇
  2023年   77篇
  2022年   41篇
  2021年   279篇
  2020年   162篇
  2019年   244篇
  2018年   256篇
  2017年   204篇
  2016年   214篇
  2015年   253篇
  2014年   313篇
  2013年   462篇
  2012年   630篇
  2011年   602篇
  2010年   294篇
  2009年   290篇
  2008年   456篇
  2007年   461篇
  2006年   422篇
  2005年   421篇
  2004年   319篇
  2003年   235篇
  2002年   251篇
  2001年   64篇
  2000年   46篇
  1999年   51篇
  1998年   37篇
  1997年   20篇
  1996年   18篇
  1995年   23篇
  1994年   21篇
  1993年   25篇
  1992年   45篇
  1991年   35篇
  1990年   33篇
  1989年   34篇
  1988年   30篇
  1987年   36篇
  1986年   33篇
  1985年   40篇
  1984年   33篇
  1983年   25篇
  1982年   17篇
  1980年   11篇
  1979年   16篇
  1978年   16篇
  1977年   20篇
  1975年   15篇
  1974年   14篇
  1972年   14篇
  1970年   10篇
排序方式: 共有7742条查询结果,搜索用时 31 毫秒
1.
Ask any clinical ethics consultant, and they can tell you about their transformative cases. Some stick with us because all roads led nowhere. Cassandra Lee had a history of pulling out lines and tubes and a distaste of warming blankets. Her admission marked her thirtieth over the past year. Many of the challenges facing the hospital caring for her were not unique: significant psychiatric issues, prolonged nonadherence to medical advice, and end‐of‐life decision‐making combined to create an ethically dense and vexing situation. Ms. Lee, like so many patients, was suffering because of system failures.  相似文献   
2.
3.
4.
Reston virus (RESTV), an ebolavirus, causes clinical disease in macaques but has yet only been associated with rare asymptomatic infections in humans. Its 2008 emergence in pigs in the Philippines raised concerns about food safety, pathogenicity, and zoonotic potential, questions that are still unanswered. Until today, the virulence of RESTV for pigs has remained elusive, with unclear pathogenicity in naturally infected animals and only one experimental study demonstrating susceptibility and evidence for shedding but no disease. Here we show that combined oropharyngeal and nasal infection of young (3- to 7-wk-old) Yorkshire cross pigs with RESTV resulted in severe respiratory disease, with most animals reaching humane endpoint within a week. RESTV-infected pigs developed severe cyanosis, tachypnea, and acute interstitial pneumonia, with RESTV shedding from oronasal mucosal membranes. Our studies indicate that RESTV should be considered a livestock pathogen with zoonotic potential.

Reston virus (RESTV) was discovered in 1989/1990 in macaques imported into the United States from the Philippines for research purposes (1). Since then, there have been several episodes of disease caused by RESTV in macaques and rare asymptomatic infections in humans (2, 3). Unexpectedly, in 2008, RESTV emerged in pigs in the Philippines, and, shortly thereafter, RESTV sequences were detected in Chinese swine, raising zoonotic and food safety concerns (4, 5). RESTV constitutes a separate species in the genus Ebolavirus, family Filoviridae, and is generally thought of as the human apathogenic filovirus (6). Aside from humans (2, 3), RESTV has been shown to naturally and experimentally infect macaques, swine, ferrets, bats, and several rodent species (4, 5, 713). Upon experimental infection, macaques and ferrets, as well as immunocompromised rodents, such as STAT-1 knockout mice, develop severe disease with lethal outcome, whereas immunocompetent rodents generally do not (912). Whether RESTV itself causes disease in naturally infected domestic pigs remains unknown, since the RESTV-infected pigs from the Philippines were coinfected with the virulent arterivirus porcine reproductive and respiratory syndrome virus (PRRSV; now Betaarterivirus suid 1). In an initial experimental study, domestic pigs infected with RESTV only exhibited subclinical infections with evidence for virus shedding (7). We studied RESTV infection in young (3- to 7-wk-old) Yorkshire cross pigs, a swine breed used frequently in commercial pig production systems around the world. The main objective was to determine an age-dependent susceptibility to infection.  相似文献   
5.
Cognitive Therapy and Research - Despite interest in psychological inflexibility as a marker of suicide risk, no measure of psychological inflexibility specific to SI exists. The present study...  相似文献   
6.
7.
Many pregnant women rely on their health professional for nutrition information during routine antenatal visits. This review offers information to assist health professionals with advising pregnant women of the important nutrition considerations during pregnancy. The roles of some of the key nutrients are discussed, including folic acid, iodine, iron, calcium, and vitamin D. Recommendations for each of the key nutrients are covered and examples of how these can be achieved are presented. The review also details additional nutritional considerations that should be discussed during antenatal consults, including energy balance and weight gain recommendations, the importance of food safety during pregnancy, the recommended safe levels of consumption of vitamin A, caffeine, and fish, and the importance of abstaining from alcohol. Educating and supporting women during pregnancy to make healthy food choices to fulfil their needs and the needs of their growing fetus, will help to promote a healthy start to life.  相似文献   
8.
9.
Time series analyses are statistical methods used to assess trends in repeated measurements taken at regular intervals and their associations with other trends or events, taking account of the temporal structure of such data. Addiction research often involves assessing associations between trends in target variables (e.g. population cigarette smoking prevalence) and predictor variables (e.g. average price of a cigarette), known as a multiple time series design, or interventions or events (e.g. introduction of an indoor smoking ban), known as an interrupted time series design. There are many analytical tools available, each with its own strengths and limitations. This paper provides addiction researchers with an overview of many of the methods available (GLM, GLMM, GLS, GAMM, ARIMA, ARIMAX, VAR, SVAR, VECM) and guidance on when and how they should be used, sample size det ermination, reporting and interpretation. The aim is to provide increased clarity for researchers proposing to undertake these analyses concerning what is likely to be acceptable for publication in journals such as Addiction. Given the large number of choices that need to be made when setting up time series models, the guidance emphasizes the importance of pre‐registering hypotheses and analysis plans before the analyses are undertaken.  相似文献   
10.
BackgroundAdult imaging for blunt cerebrovascular injuries (BCVI) is based on the Denver and Memphis screening criteria where CT angiogram (CTA) is performed for any one of the criteria being positive. These guidelines have been extrapolated to the pediatric population. We hypothesize that the current adult criteria applied to pediatrics lead to unnecessary CTA in pediatric trauma patients.Study designAt our center, a 9-year retrospective study revealed that strict adherence to the Denver and Memphis criteria would have resulted in 332 unnecessary CTAs out of 2795 trauma patients with only 0.3% positive for BCVI. We also conducted a retrospective chart review of 776,355 pediatric trauma patients in the National Trauma Data Bank (NTDB) from 2007 to 2014. Data collection included children between ages 0 and 18, ICD-9 search for blunt cerebrovascular injury, and ICD-9 codes that applied to both Denver and Memphis criteria.ResultsOf 776,355 pediatric trauma activations, 81,294 pediatric patients in the NTDB fit the Denver/Memphis criteria for screening CTA neck or angiography based on ICD-9 codes, while only 2136 patients suffered BCVI. Strict utilization of the Denver/Memphis criteria would have led to a negative CTA in 79,158 (97.4%) patients. Multivariate regression analysis indicates that patients with skull base fracture, cervical spine fractures, cervical spine fracture with cervical cord injury, traumatic jugular venous injury, and cranial nerve injury should be considered part of the screening criteria for BCVI.ConclusionOur study suggests the Denver and Memphis criteria are inadequate screening criteria for CTA looking for BCVI in the pediatric blunt trauma population. New criteria are needed to adequately indicate the need for CT angiography in the pediatric trauma population.Level of evidenceIV.  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