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   3237125篇
  免费   256466篇
  国内免费   5723篇
耳鼻咽喉   47353篇
儿科学   104737篇
妇产科学   87425篇
基础医学   458816篇
口腔科学   92927篇
临床医学   294199篇
内科学   629168篇
皮肤病学   68363篇
神经病学   269484篇
特种医学   129138篇
外国民族医学   1301篇
外科学   489210篇
综合类   74546篇
现状与发展   2篇
一般理论   1268篇
预防医学   257584篇
眼科学   75881篇
药学   242031篇
  6篇
中国医学   6091篇
肿瘤学   169784篇
  2018年   34448篇
  2017年   26615篇
  2016年   29602篇
  2015年   32843篇
  2014年   46206篇
  2013年   71293篇
  2012年   96402篇
  2011年   102355篇
  2010年   60313篇
  2009年   56758篇
  2008年   97446篇
  2007年   103844篇
  2006年   104309篇
  2005年   101588篇
  2004年   98201篇
  2003年   95162篇
  2002年   93496篇
  2001年   148438篇
  2000年   154323篇
  1999年   129976篇
  1998年   37928篇
  1997年   34286篇
  1996年   34000篇
  1995年   32743篇
  1994年   30720篇
  1993年   28695篇
  1992年   103486篇
  1991年   100524篇
  1990年   97115篇
  1989年   93547篇
  1988年   86612篇
  1987年   85397篇
  1986年   80546篇
  1985年   77209篇
  1984年   58663篇
  1983年   49905篇
  1982年   30220篇
  1981年   27095篇
  1979年   54541篇
  1978年   38300篇
  1977年   32461篇
  1976年   30459篇
  1975年   32384篇
  1974年   39406篇
  1973年   37518篇
  1972年   34951篇
  1971年   32177篇
  1970年   30460篇
  1969年   28186篇
  1968年   25700篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
161.
Epidermolysis bullosa simplex (EBS) is a skin fragility disorder resulting from mutations of structural proteins in the epidermis. We provide a brief report of long‐term survival and reproduction in a mother with EBS due to keratin 5 (KRT5) c.1429G > A (p.E477K) mutation, which causes a particularly severe form of the disease.  相似文献   
162.
163.
164.
Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis.  相似文献   
165.
166.
167.
Jahn  P. 《Der Onkologe》2020,26(11):1040-1046
Die Onkologie - Die Pflegepersonaluntergrenzen als rote Linien zur Abgrenzung einer gefährlichen Pflegepraxis sind nicht geeignet, die dringend benötigte Trendwende einzuleiten und...  相似文献   
168.
169.
Geneticists have, for years, understood the nature of genome‐wide association studies using common genomic variants. Recently, however, focus has shifted to the analysis of rare variants. This presents potential problems for researchers, as rare variants do not always behave in the same way common variants do, sometimes rendering decades of solid intuition moot. In this paper, we present examples of the differences between common and rare variants. We show why one must be significantly more careful about the origin of rare variants, and how failing to do so can lead to highly inflated type I error. We then explain how to best avoid such concerns with careful understanding and study design. Additionally, we demonstrate that a seemingly low error rate in next‐generation sequencing can dramatically impact the false‐positive rate for rare variants. This is due to the fact that rare variants are, by definition, seen infrequently, making it hard to distinguish between errors and real variants. Compounding this problem is the fact that the proportion of errors is likely to get worse, not better, with increasing sample size. One cannot simply scale their way up in order to solve this problem. Understanding these potential pitfalls is a key step in successfully identifying true associations between rare variants and diseases.  相似文献   
170.
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