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   1697064篇
  免费   126266篇
  国内免费   6813篇
耳鼻咽喉   20051篇
儿科学   54471篇
妇产科学   43438篇
基础医学   226708篇
口腔科学   41674篇
临床医学   149967篇
内科学   346637篇
皮肤病学   34942篇
神经病学   144338篇
特种医学   70210篇
外国民族医学   287篇
外科学   267893篇
综合类   37030篇
现状与发展   4篇
一般理论   667篇
预防医学   140895篇
眼科学   34586篇
药学   115956篇
  6篇
中国医学   3158篇
肿瘤学   97225篇
  2019年   11792篇
  2018年   38588篇
  2017年   30776篇
  2016年   36121篇
  2015年   18603篇
  2014年   25712篇
  2013年   37816篇
  2012年   53728篇
  2011年   71624篇
  2010年   49496篇
  2009年   41653篇
  2008年   68089篇
  2007年   74452篇
  2006年   52041篇
  2005年   53139篇
  2004年   52556篇
  2003年   52438篇
  2002年   47923篇
  2001年   67979篇
  2000年   69771篇
  1999年   58501篇
  1998年   19240篇
  1997年   17320篇
  1996年   17977篇
  1995年   17944篇
  1994年   16693篇
  1993年   15604篇
  1992年   48178篇
  1991年   46772篇
  1990年   44932篇
  1989年   42687篇
  1988年   39632篇
  1987年   38985篇
  1986年   36743篇
  1985年   35561篇
  1984年   27626篇
  1983年   23372篇
  1982年   15457篇
  1981年   13819篇
  1980年   13126篇
  1979年   24279篇
  1978年   17911篇
  1977年   15163篇
  1976年   13929篇
  1975年   14283篇
  1974年   16672篇
  1973年   15888篇
  1972年   14520篇
  1971年   13328篇
  1970年   12177篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Imaging     
  相似文献   
62.
63.
64.
65.
For patients who receive a liver transplant (LTX) for alcoholic liver disease (ALD), investigators are focusing beyond survival to determine specific alcohol use outcomes. Studies suggest the use of alcohol ranges from 8 to 22% for the first post-transplant year with cumulative rates reaching 30 to 40% by 5 years following transplantation. Yet while investigators are interested in determining specific rates of alcohol use and predictors of use, only three studies since 1990 have been prospective. In 1998, we began a prospective study of post-LTX alcohol consumption in ALD recipients using multiple repeated measures of alcohol use. After 5 years of follow-up, we found that 22% had used any alcohol by the first year and 42% had a drink by 5 years. By 5 years, 26% drank at a heavier use (binge) pattern and 20% drank in a frequent pattern. In a univariate model, predictors of alcohol use included pre-transplant length of sobriety, a diagnosis of alcohol dependence, a history of other substance use, and prior alcohol rehabilitation.  相似文献   
66.
Background: Few studies have examined the use of ultrasound for sciatic nerve localization. The authors evaluated the usefulness of low-frequency ultrasound in identifying the sciatic nerve at three locations in the lower extremity and in guiding needle advancement to target before nerve stimulation.

Methods: In this prospective observational study, 15 volunteers underwent sciatic nerve examination using a curved ultrasound probe in the range of 2-5 MHz and a Philips-ATL 5000 unit (ATL Ultrasound, Bothell, WA) in the gluteal, infragluteal, and proximal thigh regions. Thereafter, an insulated block needle was advanced inline with the ultrasound beam to reach the nerve target, which was further confirmed by electrical stimulation. The quality of sciatic nerve images, ease of needle to nerve contact, threshold stimulating current, and resultant motor response were recorded.

Results: The sciatic nerve was successfully identified in the transverse view as a solitary predominantly hyperechoic structure on ultrasound in all of the three regions examined. The target nerve was visualized easily in 87% and localized within two needle attempts in all patients. Nerve stimulation was successful in 100% after two attempts with a threshold current of 0.42 +/- 0.12 (mean +/- SD) eliciting foot plantarflexion or dorsiflexion.  相似文献   

67.
Infections due to Penicillium species other than P.marneffei are rare. We identified a boy with X-linked chronic granulomatous disease (X-CGD) with a pulmonary nodule and adjacent rib osteomyelitis caused by Penicillium piceum. The only sign of infection was an elevated sedimentation rate. P. piceum was isolated by fine needle aspirate and from excised infected tissues. Surgical removal and one year of voriconazole treatment were very well tolerated and led to complete recovery. Microbiological, microscopic and molecular studies support the fungal diagnosis. P. piceum should be considered as a relevant pathogen in immunocompromised patients.  相似文献   
68.
Phenylketonuria (PKU), an inborn error of phenylalanine metabolism, has been shown to be a risk factor for tardive dyskinesia (TD). In male psychiatric patients there was a significant relationship between TD and measures of plasma phenylalanine following ingestion of a standardized phenylalanine dose that was indicative of higher brain availability of phenylalanine in patients with TD. In addition, a medical food formulation consisting of branched chain amino acids, which compete with phenylalanine for transport across the blood-brain barrier, has been demonstrated to be an efficacious treatment for TD. Cumulatively these findings suggested that TD was related to phenylalanine metabolism and thus that sequence variants in the gene for phenylalanine hydroxylase (PAH), the rate-limiting enzyme in the catabolism of phenylalanine, could be associated with TD susceptibility. Genetic screening of PAH in a group of 123 psychiatric patients revealed ten sequence polymorphisms and two mutations, but none appeared to be a significant risk factor for TD.  相似文献   
69.
70.
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