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   1074814篇
  免费   73321篇
  国内免费   1371篇
耳鼻咽喉   15023篇
儿科学   34651篇
妇产科学   28652篇
基础医学   153621篇
口腔科学   29587篇
临床医学   94918篇
内科学   203839篇
皮肤病学   24429篇
神经病学   81615篇
特种医学   43096篇
外国民族医学   201篇
外科学   163554篇
综合类   21700篇
现状与发展   1篇
一般理论   263篇
预防医学   74573篇
眼科学   24535篇
药学   86202篇
  7篇
中国医学   2807篇
肿瘤学   66232篇
  2019年   7792篇
  2018年   11326篇
  2017年   8952篇
  2016年   10149篇
  2015年   11298篇
  2014年   15331篇
  2013年   22273篇
  2012年   30661篇
  2011年   32423篇
  2010年   19017篇
  2009年   17889篇
  2008年   30050篇
  2007年   32177篇
  2006年   32824篇
  2005年   31162篇
  2004年   29829篇
  2003年   28661篇
  2002年   27642篇
  2001年   60070篇
  2000年   61536篇
  1999年   50987篇
  1998年   12468篇
  1997年   11025篇
  1996年   11041篇
  1995年   10348篇
  1994年   9359篇
  1993年   8865篇
  1992年   37824篇
  1991年   36304篇
  1990年   35791篇
  1989年   34308篇
  1988年   30881篇
  1987年   30011篇
  1986年   28238篇
  1985年   26472篇
  1984年   19195篇
  1983年   16124篇
  1982年   8827篇
  1979年   17036篇
  1978年   11411篇
  1977年   10231篇
  1976年   8838篇
  1975年   10072篇
  1974年   11653篇
  1973年   11290篇
  1972年   10761篇
  1971年   10096篇
  1970年   9265篇
  1969年   8945篇
  1968年   7926篇
排序方式: 共有10000条查询结果,搜索用时 251 毫秒
141.
142.
Objective: Asthma disproportionately impacts and has poorer outcomes in low-income, minority, and inner-city children. The home environment has a profound impact on a child's asthma. Home-based asthma visits have the potential to positively impact a child's asthma, especially in targeted populations. The purpose of this integrative review is 1.) to explore the effectiveness of home-based education and environmental measures and 2.) to explore specific indicators and tools to measure pediatric asthma control and program effectiveness. Data Sources: Medline, CINHAL, and Ovid databases were searched from 2010 to 2017 utilizing the keywords healthy homes AND asthma and home based interventions AND asthma. Study Selections: A total of 71 articles were retrieved of which 27 articles met the inclusion criteria of English language, human subjects, and the inclusion of pediatric populations. Three additional articles were hand-searched from previous references. In total, 30 articles were reviewed. A quality appraisal was conducted utilizing standardized appraisal tools. Results: Home-based asthma education and environmental interventions have proven to be effective. The programs reviewed varied in types of interventions, intensity and duration, the type of provider, length of follow-up, and outcome measures. Successful programs were patient-centered, included a home assessment and individualized education and interventions, and were collaborative. Multiple outcome indicators such as health care utilization, asthma control, missed days of school or productivity, asthma symptoms, and verification of environmental remediation have been utilized. Conclusion: Home-based asthma programs can be beneficial to children with poorly controlled asthma and have the potential to be cost-effective.  相似文献   
143.
Electrocardiogram (ECG) signal gives a lot of information on the physiology of heart. In reality, noise from various sources interfere with the ECG signal. To get the correct information on physiology of the heart, noise cancellation of the ECG signal is required. In this paper, the effectiveness of extended Kalman smoother (EKS) with the differential evolution (DE) technique for noise cancellation of the ECG signal is investigated. DE is used as an automatic parameter selection method for the selection of ten optimized components of the ECG signal, and those are used to create the ECG signal according to the real ECG signal. These parameters are used by the EKS for the development of the state equation and also for initialization of the parameters of EKS. EKS framework is used for denoising the ECG signal from the single channel. The effectiveness of proposed noise cancellation technique has been evaluated by adding white, colored Gaussian noise and real muscle artifact noise at different SNR to some visually clean ECG signals from the MIT-BIH arrhythmia database. The proposed noise cancellation technique of ECG signal shows better signal to noise ratio (SNR) improvement, lesser mean square error (MSE) and percent of distortion (PRD) compared to other well-known methods.  相似文献   
144.
Infantile hemangiomas (IHs) are the most common benign tumor of infancy, characterized by a natural history of early proliferation in the first months of life to eventual involution during childhood, often with residual fibrofatty tissue. Once involution has been achieved, IHs do not typically recur. We present two cases of exogenous growth hormone therapy resulting in the recurrence of IHs in late childhood, supported by radiological, immunohistochemical, in vitro, and in vivo evidence.  相似文献   
145.
146.
147.
148.

Aims

Variations of the anatomy of donor hepatic arteries increase the number of arterial anastomoses during liver transplantation and, possibly, the incidence of hepatic artery thrombosis (HAT). In this study, we describe the arterial anatomic variations in liver grafts procured and transplanted by a single center in Greece, the techniques of arterial anastomosis, and their effect on the incidence of early HAT.

Materials and Methods

From January 2013 to December 2017, the arterial anatomy of 116 grafts procured for liver transplantation were recorded, as well as the technique of arterial anastomosis and the incidence of early hepatic artery thrombosis (HAT <30 days).

Results

A single hepatic artery was recorded in 72.41% of the procured grafts, an aberrant left hepatic artery (accessory or replaced) in 18 grafts (15.52%), and an aberrant right hepatic artery (accessory or replaced) in 17 grafts (14.66%), while other variations were observed in less than 1% of the procured livers. Of the 116 primary liver transplantations, 6 patients (5.17%) developed early HAT <30 days. Two of these patients (1.72%) had 1 anastomosis of the hepatic artery and 4 (3.45%) had 2 anastomoses due to anatomic variations.

Conclusions

Anatomic variations of the hepatic artery in liver grafts is a common finding and increase the incidence of early HAT but not to a degree to make these grafts unusable.  相似文献   
149.
150.
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