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   1375824篇
  免费   103236篇
  国内免费   2645篇
耳鼻咽喉   18131篇
儿科学   42671篇
妇产科学   36656篇
基础医学   207708篇
口腔科学   37583篇
临床医学   128376篇
内科学   267461篇
皮肤病学   30942篇
神经病学   111156篇
特种医学   53361篇
外国民族医学   265篇
外科学   193587篇
综合类   26207篇
现状与发展   6篇
一般理论   594篇
预防医学   110443篇
眼科学   30965篇
药学   103196篇
  6篇
中国医学   3435篇
肿瘤学   78956篇
  2021年   13598篇
  2019年   12748篇
  2018年   16932篇
  2017年   13129篇
  2016年   14996篇
  2015年   18224篇
  2014年   24097篇
  2013年   34561篇
  2012年   48147篇
  2011年   50070篇
  2010年   28887篇
  2009年   27225篇
  2008年   44733篇
  2007年   47010篇
  2006年   45903篇
  2005年   44694篇
  2004年   42361篇
  2003年   40138篇
  2002年   38471篇
  2001年   58469篇
  2000年   59291篇
  1999年   49870篇
  1998年   14203篇
  1997年   12825篇
  1996年   13091篇
  1995年   12321篇
  1994年   11440篇
  1992年   38829篇
  1991年   38248篇
  1990年   36963篇
  1989年   35701篇
  1988年   33073篇
  1987年   32409篇
  1986年   30792篇
  1985年   29072篇
  1984年   22147篇
  1983年   19339篇
  1982年   11469篇
  1979年   21124篇
  1978年   15520篇
  1977年   12886篇
  1976年   11957篇
  1975年   12913篇
  1974年   15705篇
  1973年   15445篇
  1972年   14575篇
  1971年   13610篇
  1970年   12815篇
  1969年   12097篇
  1968年   11263篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.

Interstitial lung disease (ILD) represents a significant cause of morbidity and mortality in systemic sclerosis (SSc). The purpose of this study was to examine recirculating lymphocytes from SSc patients for potential biomarkers of interstitial lung disease (ILD). Peripheral blood mononuclear cells (PBMCs) were isolated from patients with SSc and healthy controls enrolled in the Vanderbilt University Myositis and Scleroderma Treatment Initiative Center cohort between 9/2017–6/2019. Clinical phenotyping was performed by chart abstraction. Immunophenotyping was performed using both mass cytometry and fluorescence cytometry combined with t-distributed stochastic neighbor embedding analysis and traditional biaxial gating. This study included 34 patients with SSc-ILD, 14 patients without SSc-ILD, and 25 healthy controls. CD21lo/neg cells are significantly increased in SSc-ILD but not in SSc without ILD (15.4 ± 13.3% vs. 5.8 ± 0.9%, p = 0.002) or healthy controls (5.0 ± 0.5%, p < 0.0001). While CD21lo/neg B cells can be identified from a single biaxial gate, tSNE analysis reveals that the biaxial gate is comprised of multiple distinct subsets, all of which are increased in SSc-ILD. CD21lo/neg cells in both healthy controls and SSc-ILD are predominantly tBET positive and do not have intracellular CD21. Immunohistochemistry staining demonstrated that CD21lo/neg B cells diffusely infiltrate the lung parenchyma of an SSc-ILD patient. Additional work is needed to validate this biomarker in larger cohorts and longitudinal studies and to understand the role of these cells in SSc-ILD.

  相似文献   
2.
3.
4.
Social Psychiatry and Psychiatric Epidemiology - The negative effect of catastrophic financial loss on suicide risk is widely perceived but hardly studied in-depth because of various difficulties...  相似文献   
5.
6.
7.
Journal of Behavioral Medicine - Evidence supports the use of graphic warnings to educate the public about the health harms of smoking and suggests warnings eliciting negative emotional responses...  相似文献   
8.
Noninvasive imaging of cardiac fibrosis is important for early diagnosis and intervention in chronic heart diseases. Here, we investigated whether noninvasive, contrast agent-free MRI T2-mapping can quantify myocardial fibrosis in preclinical models of aging and pressure overload. Myocardial fibrosis and remodeling were analyzed in two animal models: (i) aging (15-month-old male CF-1 mice vs. young 6- to 8-week-old mice), and (ii) pressure overload (PO; by transverse aortic constriction in 4- to 5-month-old male C57BL/6 mice vs. sham-operated for 14 days). In vivo T2-mapping was performed by acquiring data during the isovolumic and early diastolic phases, with a modified respiratory and ECG-triggered multiecho TurboRARE sequence on a 7-T MRI. Cine MRI provided cardiac morphology and function. A quantitative segmentation method was developed to analyze the in vivo T2-maps of hearts at midventricle, apex, and basal regions. The cardiac fibrosis area was analyzed ex vivo by picro sirius red (PSR) staining. Both aged and pressure-overloaded hearts developed significant myocardial contractile dysfunction, cardiac hypertrophy, and interstitial fibrosis. The aged mice had two phenotypes, fibrotic and mild-fibrotic. Notably, the aged fibrotic subgroup and the PO mice showed a marked decrease in T2 relaxation times (25.3 ± 0.6 in aged vs. 29.9 ± 0.7 ms in young mice, p = 0.002; and 24.3 ± 1.7 in PO vs. 28.7 ± 0.7 ms in shams, p = 0.05). However, no significant difference in T2 was detected between the aged mild-fibrotic subgroup and the young mice. Accordingly, an inverse correlation between myocardial fibrosis percentage (FP) and T2 relaxation time was derived (R2 = 0.98): T2 (ms) = 30.45 – 1.05 × FP. Thus, these results demonstrate a statistical agreement between T2-map–quantified fibrosis and PSR staining in two different clinically relevant animal models. In conclusion, T2-mapping MRI is a promising noninvasive contrast agent-free quantitative technique to characterize myocardial fibrosis.  相似文献   
9.
10.
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