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   9298篇
  免费   730篇
  国内免费   20篇
耳鼻咽喉   78篇
儿科学   277篇
妇产科学   209篇
基础医学   1254篇
口腔科学   145篇
临床医学   1635篇
内科学   1554篇
皮肤病学   97篇
神经病学   845篇
特种医学   187篇
外科学   791篇
综合类   121篇
一般理论   11篇
预防医学   1566篇
眼科学   113篇
药学   569篇
中国医学   1篇
肿瘤学   595篇
  2023年   95篇
  2022年   53篇
  2021年   170篇
  2020年   139篇
  2019年   238篇
  2018年   238篇
  2017年   208篇
  2016年   204篇
  2015年   244篇
  2014年   334篇
  2013年   478篇
  2012年   736篇
  2011年   723篇
  2010年   366篇
  2009年   326篇
  2008年   585篇
  2007年   642篇
  2006年   601篇
  2005年   628篇
  2004年   534篇
  2003年   571篇
  2002年   512篇
  2001年   82篇
  2000年   72篇
  1999年   94篇
  1998年   117篇
  1997年   80篇
  1996年   56篇
  1995年   58篇
  1994年   61篇
  1993年   68篇
  1992年   49篇
  1991年   45篇
  1990年   44篇
  1989年   45篇
  1988年   48篇
  1987年   41篇
  1986年   49篇
  1985年   37篇
  1984年   52篇
  1983年   38篇
  1982年   33篇
  1981年   35篇
  1980年   36篇
  1979年   24篇
  1978年   16篇
  1977年   17篇
  1974年   12篇
  1973年   13篇
  1972年   12篇
排序方式: 共有10000条查询结果,搜索用时 24 毫秒
1.
2.
3.
4.
Capillary malformation–arteriovenous malformation syndrome (CM‐AVM) is an autosomal dominant disorder caused by RASA1 mutations. The prevalence and phenotypic spectrum are unknown. Evaluation of patients with multiple CMs is challenging because associated AVMs can be life threatening. The objective of this study was to describe the clinical characteristics of children presenting with features of CM‐AVM to an academic pediatric dermatology practice. After institutional review board approval was received, a retrospective chart review was performed of patients presenting between 2009 and 2012 with features of CM‐AVM. We report nine cases. Presenting symptoms ranged from extensive vascular stains and cardiac failure to CMs noted incidentally during routine skin examination. All demonstrated multiple CMs, two had Parkes Weber syndrome, and two had multiple infantile hemangiomas. Seven patients had family histories of multiple CMs; three had family histories of large, atypical CMs. Six had personal or family histories of AVMs. Genetic evaluation was recommended for all and was pursued by six families; four RASA1 mutations were identified, including one de novo. Consultations with neurology, cardiology, and orthopedics were recommended. Most patients (89%) have not required treatment to date. CM‐AVM is an underrecognized condition with a wide clinical spectrum that often presents in childhood. Further evaluation may be indicated in patients with multiple CMs. This study is limited by its small and retrospective nature.  相似文献   
5.
6.
7.
ABSTRACT

Forensic DNA analysis is dependent on comparing the known and the unknown. Expand the number of known profiles, and the likelihood of a successful match increases. Forensic use of DNA is moving towards comparing samples of unknown origin with publicly available genetic data, such as the records held by genetic genealogy providers. Use of forensic genetic genealogy has yielded a number of recent high-profile successes but has raised ethical and privacy concerns. Navigating family trees is complex, even more so when combined with a comparison of genetic relationships. This intelligence-gathering process has led to occasional false leads, and its use also risks a public backlash, similar to concerns over Cambridge Analytica. A cautious approach to use of this technique is therefore warranted.  相似文献   
8.
9.
10.
The adult mammalian central nervous system (CNS) lacks the capacity to support axonal regeneration. There is increasing evidence to suggest that astrocytes, the major glial population in the CNS, may possess both axon-growth promoting and axon-growth inhibitory properties and the latter may contribute to the poor regenerative capacity of the CNS. In order to examine the molecular differences between axon-growth permissive and axon-growth inhibitory astrocytes, a panel of astrocyte cell lines exhibiting a range of axon-growth promoting properties was generated and analysed. No clear correlation was found between the axon-growth promoting properties of these astrocyte cell lines with: (i) the expression of known neurite-outgrowth promoting molecules such as laminin, fibronectin andN-cadherin; (ii) the expression of known inhibitory molecules such tenascin and chondroitin sulphate proteoglycan; (iii) plasminogen activator and plasminogen activator inhibitor activity; and (iv) growth cone collapsing activity. EM studies on aggregates formed from astrocyte cell lines, however, revealed the presence of an abundance of extracellular matrix material associated with the more inhibitory astrocyte cell lines. When matrix deposited by astrocyte cell lines was assessed for axon-growth promoting activity, matrix from permissive lines was found to be a good substrate, whereas matrix from the inhibitory astrocyte lines was a poor substrate for neuritic growth. Our findings, taken together, suggest that the functional differences between the permissive and the inhibitory astrocyte cell lines reside largely with the ECM.  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