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   1510977篇
  免费   111514篇
  国内免费   1956篇
耳鼻咽喉   20069篇
儿科学   49904篇
妇产科学   43668篇
基础医学   226177篇
口腔科学   41178篇
临床医学   138553篇
内科学   293516篇
皮肤病学   32596篇
神经病学   119756篇
特种医学   56658篇
外国民族医学   305篇
外科学   217965篇
综合类   32467篇
现状与发展   4篇
一般理论   728篇
预防医学   122277篇
眼科学   34026篇
药学   110293篇
  7篇
中国医学   2650篇
肿瘤学   81650篇
  2018年   16476篇
  2017年   12536篇
  2016年   13835篇
  2015年   15937篇
  2014年   21912篇
  2013年   33706篇
  2012年   45252篇
  2011年   48016篇
  2010年   28305篇
  2009年   26968篇
  2008年   45083篇
  2007年   48428篇
  2006年   47955篇
  2005年   46723篇
  2004年   44910篇
  2003年   42957篇
  2002年   41524篇
  2001年   66609篇
  2000年   67976篇
  1999年   57247篇
  1998年   16040篇
  1997年   14573篇
  1996年   14861篇
  1995年   14049篇
  1994年   13115篇
  1993年   12270篇
  1992年   45076篇
  1991年   44656篇
  1990年   43295篇
  1989年   41972篇
  1988年   38815篇
  1987年   37919篇
  1986年   36217篇
  1985年   34329篇
  1984年   25993篇
  1983年   22668篇
  1982年   13490篇
  1981年   12136篇
  1979年   24742篇
  1978年   18118篇
  1977年   15165篇
  1976年   14023篇
  1975年   15244篇
  1974年   18496篇
  1973年   18283篇
  1972年   17220篇
  1971年   16121篇
  1970年   15273篇
  1969年   14276篇
  1968年   13470篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.

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   
3.
4.
5.
6.
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   
7.
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   
8.
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