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   1607531篇
  免费   134230篇
  国内免费   2603篇
耳鼻咽喉   21693篇
儿科学   53237篇
妇产科学   46388篇
基础医学   228779篇
口腔科学   47322篇
临床医学   141634篇
内科学   316221篇
皮肤病学   34183篇
神经病学   130835篇
特种医学   65038篇
外国民族医学   474篇
外科学   245038篇
综合类   39912篇
现状与发展   3篇
一般理论   552篇
预防医学   123540篇
眼科学   36698篇
药学   121943篇
  2篇
中国医学   3006篇
肿瘤学   87866篇
  2018年   14956篇
  2016年   13066篇
  2015年   15205篇
  2014年   20944篇
  2013年   31738篇
  2012年   43177篇
  2011年   45421篇
  2010年   26670篇
  2009年   25645篇
  2008年   43536篇
  2007年   45898篇
  2006年   46679篇
  2005年   45290篇
  2004年   44640篇
  2003年   42713篇
  2002年   41758篇
  2001年   75762篇
  2000年   78391篇
  1999年   66459篇
  1998年   17830篇
  1997年   16436篇
  1996年   16392篇
  1995年   16091篇
  1994年   15128篇
  1993年   14285篇
  1992年   55484篇
  1991年   53806篇
  1990年   52598篇
  1989年   50872篇
  1988年   47263篇
  1987年   46598篇
  1986年   44321篇
  1985年   42885篇
  1984年   32076篇
  1983年   27598篇
  1982年   16191篇
  1981年   14477篇
  1980年   13607篇
  1979年   30481篇
  1978年   21091篇
  1977年   17781篇
  1976年   16710篇
  1975年   17588篇
  1974年   21501篇
  1973年   20700篇
  1972年   18873篇
  1971年   17783篇
  1970年   16310篇
  1969年   15281篇
  1968年   13957篇
排序方式: 共有10000条查询结果,搜索用时 562 毫秒
41.
We report on a child with several café au lait spots in association with a lumbar lipomeningomyelocele as an apparently new association. Cutaneous markers, the identification of which plays a crucial role in the early diagnosis and management of spinal malformations, can accompany occult spinal dysraphism. Herein we report a case of lumbar lipomeningomyelocele associated with an overlying café au lait spot that served as a marker of occult spinal dysraphism. The patient also had segmental café au lait spots on the face, making the association unique.  相似文献   
42.
43.
44.
Bipolar disorder (BD) is a common psychiatric mood disorder affecting more than 1-2% of the general population of different European countries. Unfortunately, there is no objective laboratory-based test to aid BD diagnosis or monitor its progression, and little is known about the molecular basis of BD. Here, we performed a comparative proteomic study to identify differentially expressed plasma proteins in various BD mood states (depressed BD, manic BD, and euthymic BD) relative to healthy controls. A total of 10 euthymic BD, 20 depressed BD, 15 manic BD, and 20 demographically matched healthy control subjects were recruited. Seven high-abundance proteins were immunodepleted in plasma samples from the 4 experimental groups, which were then subjected to proteome-wide expression profiling by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight tandem mass spectrometry. Proteomic results were validated by immunoblotting and bioinformatically analyzed using MetaCore. From a total of 32 proteins identified with 1.5-fold changes in expression compared with healthy controls, 16 proteins were perturbed in BD independent of mood state, while 16 proteins were specifically associated with particular BD mood states. Two mood-independent differential proteins, apolipoprotein (Apo) A1 and Apo L1, suggest that BD pathophysiology may be associated with early perturbations in lipid metabolism. Moreover, down-regulation of one mood-dependent protein, carbonic anhydrase 1 (CA-1), suggests it may be involved in the pathophysiology of depressive episodes in BD. Thus, BD pathophysiology may be associated with early perturbations in lipid metabolism that are independent of mood state, while CA-1 may be involved in the pathophysiology of depressive episodes.  相似文献   
45.
46.
47.
48.

Background

Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease.

Methods

Resistin levels were measured in plasma and sputum from three retrospective CF cohorts spanning a wide range of disease. We also assessed the ability of neutrophils to secrete resistin upon activation in vitro. Finally, we constructed a multivariate model assessing the relationship between resistin levels and lung function.

Results

Plasma resistin levels were only marginally higher in CF than in healthy control subjects. By contrast, sputum resistin levels were very high in CF, reaching 50–100 fold higher levels than in plasma. Among CF patients, higher plasma resistin levels were associated with allergic bronchopulmonary aspergillosis, and higher sputum resistin levels were associated with CF-related diabetes. Mechanistically, in vitro release of neutrophil primary granules was concomitant with resistin secretion. Overall, sputum resistin levels were negatively correlated with CF lung function, independently of other variables (age, sex, and genotype).

Conclusions

Our data establish relationships between resistin levels in the plasma and sputum of CF patients that correlate with disease status, and identify resistin as a novel mechanistic link between neutrophilic inflammation and lung disease in CF.  相似文献   
49.
50.
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