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   2552570篇
  免费   200142篇
  国内免费   3974篇
耳鼻咽喉   36304篇
儿科学   86660篇
妇产科学   72159篇
基础医学   363204篇
口腔科学   72926篇
临床医学   226223篇
内科学   499350篇
皮肤病学   55035篇
神经病学   204654篇
特种医学   101845篇
外国民族医学   1066篇
外科学   388264篇
综合类   59972篇
现状与发展   4篇
一般理论   875篇
预防医学   197355篇
眼科学   58568篇
药学   191719篇
  5篇
中国医学   4756篇
肿瘤学   135742篇
  2018年   24934篇
  2016年   21229篇
  2015年   24294篇
  2014年   33736篇
  2013年   51772篇
  2012年   70308篇
  2011年   74468篇
  2010年   44312篇
  2009年   42155篇
  2008年   71274篇
  2007年   75661篇
  2006年   76531篇
  2005年   74533篇
  2004年   73017篇
  2003年   70144篇
  2002年   68743篇
  2001年   119770篇
  2000年   124248篇
  1999年   105517篇
  1998年   29040篇
  1997年   26315篇
  1996年   26594篇
  1995年   25664篇
  1994年   24195篇
  1993年   22637篇
  1992年   86083篇
  1991年   83948篇
  1990年   82157篇
  1989年   78818篇
  1988年   73096篇
  1987年   72001篇
  1986年   67938篇
  1985年   65505篇
  1984年   49101篇
  1983年   42063篇
  1982年   24681篇
  1981年   22207篇
  1980年   20507篇
  1979年   46012篇
  1978年   32101篇
  1977年   27073篇
  1976年   25481篇
  1975年   27193篇
  1974年   32736篇
  1973年   31539篇
  1972年   29008篇
  1971年   26892篇
  1970年   24990篇
  1969年   23208篇
  1968年   21203篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Choledochojejunostomy (CJS) is commonly used for biliary reconstruction in liver transplantation for primary sclerosing cholangitis (PSC). We alternatively performed choledochoduodenostomy (CDS) and side-to-side choledochodocholedochstomy in a large cohort of patients. Fifty-one patients with PSC, transplanted between 1988 and 2000, were analyzed retrospectively. Biliary reconstruction was CDS in 25 (49%), CJS in 20 (39%) and CC in 6 transplantations (12%). Biliary leaks occurred in the early follow-up (< or =41 days) only in CDS patients (20%). However, in the late follow-up (>4 months), stricturing of anastomosis was found once in CDS (4%) and CJS (5%). Later (>9 months), intrahepatic bile duct strictures were diagnosed in four CDS (16%), one CJS (5%) and one CC (17%) patient(s). In 48% of CDS (12/25), 60% of CJS (12/20) and 17% of CC (1/6) at least one incidence of cholangitis was observed. Overall, biliary complication rates were significantly higher in CDS (40%) than CJS (10%) and CC (17%); of those none in CC and 12% in CDS were anastomosis-related. Graft/patient survival showed no significant differences among groups. Based on our results we consider CJS the standard method for biliary reconstruction in PSC; however, in selected cases where CJS is difficult to accomplish because of previous surgery or for retransplantation, CDS may present an alternative technique.  相似文献   
72.
The precise molecular cause of insulin resistance has not yet been elucidated. Resistance to the normal action of insulin contributes to the pathogenesis of a number of common human disorders, including type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetes mellitus, hypertension, and the Metabolic Syndrome X, thus constituting a major public health problem. A disease program aimed at combating this disorder should focus on the identification of targets for therapeutic intervention which may overcome insulin resistance and hence the associated metabolic consequences characteristic of the Metabolic Syndrome. Although the primary defect in the pathogenesis of type 2 diabetes is unknown, genetic and environmental factors are likely to contribute to the manifestation of this progressive metabolic disorder, which is usually not clinically apparent until mid-life. Defects at the level of glucose uptake/phosphorylation characterize insulin resistance in skeletal muscle of type 2 diabetic patients. Identification of putative components of the insulin receptor-signaling pathway may offer insights into mechanisms involved in insulin resistance. Enhanced flux of free fatty acids due to impaired lipid metabolism may contribute to impaired insulin secretion and peripheral insulin resistance. Genes regulating lipolysis are prime candidates for susceptibility towards the metabolic syndrome. Here we describe pathways constituting complex interactions that control glucose homeostasis. We will be considering (1) regulation of glucose uptake by the insulin receptor signaling pathway, and (2) control of adipogenesis and insulin sensitivity by the sterol response element binding protein (SREBP) pathway.  相似文献   
73.
74.
75.
76.
77.
78.
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   

79.
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   
80.
Abstract: Background: Fetal pulse oximetry improves the assessment of fetal well‐being during labor. The objective of this study was to evaluate women's satisfaction with their experience with this additional technology. Methods: We surveyed women participating in the FOREMOST trial, a randomized controlled trial comparing the addition of fetal pulse oximetry (FPO) to conventional cardiotocograph (CTG) monitoring (intervention group), versus CTG‐only (control group), in the presence of nonreassuring fetal status during labor. Our survey evaluated 3 aspects of women's experience: labor, fetal monitoring, and participation in the research. The survey was administered within a few days of giving birth and repeated 3 months later. Results: No differences were found between the intervention and control groups for women's evaluations of their labor, fetal monitoring, research, or overall experiences when surveyed on both occasions. Within each study group, a small but statistically significant decline occurred in women's scores for their experience of labor and overall experience from the initial survey close to the time of giving birth, to 3 months later. The magnitude of differences in responses over time was similar for the both groups. Women were more satisfied after a spontaneous or assisted vaginal birth than after cesarean section. Length of time the research midwife was present had a significant positive effect on women's ratings of their experience several days after giving birth (p = 0.006), but no effect at 3 months. Conclusions: The addition of fetal pulse oximetry for the assessment of fetal well‐being during labor did not affect childbearing women's perceptions of fetal monitoring or their labor. Women evaluated their experience in the research process positively overall. Small changes occurred in women's perception of their satisfaction over time. (BIRTH 33:2 June 2006)  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