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   1325篇
  免费   122篇
  国内免费   18篇
耳鼻咽喉   10篇
儿科学   62篇
妇产科学   17篇
基础医学   210篇
口腔科学   49篇
临床医学   125篇
内科学   225篇
皮肤病学   12篇
神经病学   84篇
特种医学   275篇
外科学   130篇
综合类   43篇
一般理论   1篇
预防医学   106篇
眼科学   19篇
药学   48篇
中国医学   1篇
肿瘤学   48篇
  2022年   7篇
  2021年   14篇
  2020年   14篇
  2018年   12篇
  2017年   19篇
  2016年   21篇
  2015年   15篇
  2014年   21篇
  2013年   37篇
  2012年   47篇
  2011年   46篇
  2010年   47篇
  2009年   49篇
  2008年   66篇
  2007年   47篇
  2006年   39篇
  2005年   42篇
  2004年   36篇
  2003年   46篇
  2002年   31篇
  2001年   22篇
  2000年   29篇
  1999年   29篇
  1998年   50篇
  1997年   54篇
  1996年   39篇
  1995年   29篇
  1994年   45篇
  1993年   28篇
  1992年   20篇
  1991年   23篇
  1990年   22篇
  1989年   39篇
  1988年   31篇
  1987年   32篇
  1986年   30篇
  1985年   28篇
  1984年   18篇
  1983年   23篇
  1982年   18篇
  1981年   30篇
  1980年   9篇
  1979年   18篇
  1978年   16篇
  1977年   17篇
  1976年   15篇
  1975年   18篇
  1974年   9篇
  1970年   6篇
  1968年   6篇
排序方式: 共有1465条查询结果,搜索用时 46 毫秒
1.
Background: Dense deposit disease and atypical hemolytic uremic syndrome are often caused by Complement Factor H (CFH) mutations. This study describes the retinal abnormalities in dense deposit disease and, for the first time, atypical haemolytic uremic syndrome. It also reviews our understanding of drusen pathogenesis and their relevance for glomerular disease. Methods: Six individuals with dense deposit disease and one with atypical haemolytic uremic syndrome were studied from 2 to 40 years after presentation. Five had renal transplants. All four who had genetic testing had CFH mutations. Individuals underwent ophthalmological review and retinal photography, and in some cases, optical coherence tomography, and further tests of retinal function. Results: All subjects with dense deposit disease had impaired night vision and retinal drusen or whitish-yellow deposits. Retinal atrophy, pigmentation, and hemorrhage were common. In late disease, peripheral vision was restricted, central vision was distorted, and there were scotoma from sub-retinal choroidal neovascular membranes and atypical serous retinopathy. Drusen were present but less prominent in the young person with atypical uremic syndrome due to a heterozygous CFH mutation. Conclusions: Drusen are common in forms of C3 glomerulopathy caused by compound heterozygous or heterozygous CFH mutations. They are useful diagnostically but also impair vision. Drusen have an identical composition to glomerular deposits. They are also identical to the drusen of age-related macular degeneration, and may respond to the same treatments. Individuals with a C3 glomerulopathy should be assessed ophthalmologically at diagnosis, and monitored regularly for vision-threatening complications.  相似文献   
2.
3.
Non-operative management of malignant intestinal obstruction   总被引:1,自引:0,他引:1  
Intestinal obstruction is a relatively common clinical problem in patients with advanced cancer, particularly those with colorectal and ovarian tumours. A proportion of patients have a non-malignant cause for their obstruction, but in the remaining patients obstruction will be caused by advanced malignancy itself. In the past, most patients were either managed surgically or by nasogastric intestinal decompression and intravenous hydration. Surgery in patients with advanced cancer is associated with high mortality and morbidity. Effective surgical decompression is difficult. We have managed 24 patients with advanced abdominal malignancy and previous operative or radiological evidence of intestinal obstruction without operation. The technique is only appropriate for patients in whom a solitary or correctable obstructing lesion can be excluded. The patient is encouraged to take free fluid and a diet low in fibre. Intestinal colic is managed with morphine, the dose required being titrated for each individual patient against background pain and colic. Vomiting is controlled by the parenteral administration of antiemetic drugs. To simplify drug administration, morphine and metoclopramide are mixed in the same syringe and infused subcutaneously simultaneously. In our 24 patients the mean survival rate after the onset of complete obstruction was 29.2 days. The mean dose of morphine infused was 9.2 mg/h, and the mean dose of metoclopramide was 6.9 mg/h. The case of an 82-year-old male patient is presented. We commend the technique to surgeons contemplating surgery in these very difficult patients. It is simple, relatively non-invasive and saves the patients the pain, discomfort and complications of unproductive surgery.  相似文献   
4.
5.
The effect of early visual deprivation on the ability of dark- (DR) and light-reared (LR) rats to learn temporal discriminations involving sounds and lights and to abstract the intersensory correspondence involving duration from initial modality-specific training was examined in this study. While visually inexperienced DR rats were somewhat less successful in acquiring an initial discrimination involving visual events and responding to a rule reversal per se, they were as effective as their visually experienced LR counterparts in demonstrating cross-modal transfer (CMT) to signals in a new modality. The results revealed by the investigation are discussed in terms of the consequences and lack of consequences of the manipulation of early visual experience on the ontogeny of intersensory perceptual development in mammals.  相似文献   
6.
7.
8.
9.
Prevalence and Predictors of Adolescent Dating Violence   总被引:1,自引:0,他引:1  
This study of 561 rural North Carolina adolescents examined relationships among race, parental educational level, family structure, parental discipline, family violence exposure, and dating violence experiences. The sample was predominantly female (77%), with 40% black and 58% white. The subjects ranged in age from 15 to 20 years; 80% of the adolescents were 16–18. Dating violence experiences were assessed by a researcher-constructed instrument measuring warning signs of potential violence and actual violent experiences. The results suggested that recognition of abusive relationships is difficult, with many adolescents denying such a relationship but actually reporting numerous abusive events. Sixty percent had experienced violent acts during dating relationships; 24% reported extreme violence (episodes of rape, use of weapons). More than 20% of the adolescents reported family violence and 2.2% reported family sexual abuse. The study suggests new avenues for research in adolescent date violence, and for interventions with high risk groups.  相似文献   
10.
Intestinal schistosomiasis japonica: CT-pathologic correlation   总被引:1,自引:0,他引:1  
  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