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   2266775篇
  免费   177691篇
  国内免费   4073篇
耳鼻咽喉   31745篇
儿科学   74945篇
妇产科学   64725篇
基础医学   321965篇
口腔科学   65687篇
临床医学   197424篇
内科学   445272篇
皮肤病学   48529篇
神经病学   183142篇
特种医学   90943篇
外国民族医学   767篇
外科学   348390篇
综合类   54433篇
现状与发展   3篇
一般理论   768篇
预防医学   173010篇
眼科学   52561篇
药学   168776篇
  2篇
中国医学   4290篇
肿瘤学   121162篇
  2018年   21549篇
  2016年   18689篇
  2015年   21534篇
  2014年   30013篇
  2013年   46153篇
  2012年   62183篇
  2011年   65718篇
  2010年   39083篇
  2009年   37427篇
  2008年   62934篇
  2007年   66577篇
  2006年   67462篇
  2005年   65682篇
  2004年   64328篇
  2003年   61663篇
  2002年   60556篇
  2001年   104146篇
  2000年   107717篇
  1999年   91538篇
  1998年   25223篇
  1997年   23048篇
  1996年   22861篇
  1995年   22039篇
  1994年   20756篇
  1993年   19677篇
  1992年   74841篇
  1991年   72463篇
  1990年   70842篇
  1989年   68623篇
  1988年   63753篇
  1987年   62871篇
  1986年   60064篇
  1985年   57728篇
  1984年   43342篇
  1983年   37104篇
  1982年   21998篇
  1981年   19514篇
  1980年   18442篇
  1979年   40875篇
  1978年   28530篇
  1977年   24006篇
  1976年   22665篇
  1975年   24303篇
  1974年   29541篇
  1973年   28404篇
  1972年   26275篇
  1971年   24609篇
  1970年   22954篇
  1969年   21522篇
  1968年   20000篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
63.
64.
65.
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   
66.
67.
68.
69.
70.

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   
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