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   1357552篇
  免费   104348篇
  国内免费   6307篇
耳鼻咽喉   16983篇
儿科学   43830篇
妇产科学   36695篇
基础医学   200809篇
口腔科学   36383篇
临床医学   132893篇
内科学   261731篇
皮肤病学   26553篇
神经病学   113244篇
特种医学   49112篇
外国民族医学   380篇
外科学   186573篇
综合类   32739篇
现状与发展   9篇
一般理论   464篇
预防医学   115887篇
眼科学   29561篇
药学   101469篇
  21篇
中国医学   4644篇
肿瘤学   78227篇
  2021年   12222篇
  2019年   12515篇
  2018年   17146篇
  2017年   13117篇
  2016年   13969篇
  2015年   16319篇
  2014年   22270篇
  2013年   33252篇
  2012年   46000篇
  2011年   48730篇
  2010年   28307篇
  2009年   25856篇
  2008年   44020篇
  2007年   46310篇
  2006年   46373篇
  2005年   44925篇
  2004年   42428篇
  2003年   40370篇
  2002年   38991篇
  2001年   61350篇
  2000年   63069篇
  1999年   52869篇
  1998年   14987篇
  1997年   13637篇
  1996年   13428篇
  1995年   12756篇
  1994年   11888篇
  1993年   11094篇
  1992年   41751篇
  1991年   40899篇
  1990年   39568篇
  1989年   37425篇
  1988年   34668篇
  1987年   33755篇
  1986年   32210篇
  1985年   30672篇
  1984年   23059篇
  1983年   19612篇
  1982年   11760篇
  1979年   20813篇
  1978年   14816篇
  1977年   12068篇
  1976年   11877篇
  1975年   12112篇
  1974年   14800篇
  1973年   14472篇
  1972年   13356篇
  1971年   12418篇
  1970年   11485篇
  1969年   10410篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Porocarcinoma is an unusual, locally aggressive and potentially fatal neoplasm. Several cutaneous malignancies have been described in association with porocarcinoma, including squamous cell carcinoma, basal cell carcinoma and tricholemmal carcinoma. Previous reports have indicated that the occurrence of malignant tumours in combination with porocarcinoma is extremely rare, in particular with regard to Bowen disease (BD). We report an uncommon case of porocarcinoma occurring synchronously in a single BD lesion in a 63‐year‐old woman with multiple BD lesions. The clinical and histological findings confirmed this diagnosis.  相似文献   
85.
Reactive lymphoid infiltrates of the skin composed predominantly of gamma‐delta (γδ) T cells are not well described in the literature. Herein we report a case of an otherwise healthy 4‐year‐old male who presented with a waxing and waning papular rash characterized by small, discrete crusted papules spread across his trunk, face and extremities. Clinical evaluation revealed no evidence of systemic disease. Microscopic examination revealed a dermal, perivascular infiltrate of highly atypical lymphocytes with a γδ T cell phenotype, worrisome for primary cutaneous γδ T cell lymphoma. The clinical course, however, was that of a reactive condition and prompted consideration of a diagnosis of pityriasis lichenoides et varioliformis acuta (PLEVA) and lymphomatoid papulosis (LyP). In many ways, this case defies current classification schemes and seems to expand the spectrum of reactive γδ T cell infiltrates of the skin.  相似文献   
86.
87.
Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates.  相似文献   
88.
A 17‐year‐old boy presented with recurring severe dermatitis of the face of 5‐months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris.  相似文献   
89.
90.
Based on the physical randomization of completely randomized experiments, in a recent article in Statistics in Medicine, Rigdon and Hudgens propose two approaches to obtaining exact confidence intervals for the average causal effect on a binary outcome. They construct the first confidence interval by combining, with the Bonferroni adjustment, the prediction sets for treatment effects among treatment and control groups, and the second one by inverting a series of randomization tests. With sample size n, their second approach requires performing O(n4)randomization tests. We demonstrate that the physical randomization also justifies other ways to constructing exact confidence intervals that are more computationally efficient. By exploiting recent advances in hypergeometric confidence intervals and the stochastic order information of randomization tests, we propose approaches that either do not need to invoke Monte Carlo or require performing at most O(n2)randomization tests. We provide technical details and R code in the Supporting Information . Copyright © 2016 John Wiley & Sons, Ltd.  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