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   1386237篇
  免费   102913篇
  国内免费   1715篇
耳鼻咽喉   18355篇
儿科学   45213篇
妇产科学   37941篇
基础医学   207732篇
口腔科学   38797篇
临床医学   128679篇
内科学   269409篇
皮肤病学   30799篇
神经病学   114814篇
特种医学   52222篇
外国民族医学   265篇
外科学   197627篇
综合类   26276篇
现状与发展   3篇
一般理论   608篇
预防医学   111644篇
眼科学   30615篇
药学   101244篇
  6篇
中国医学   2207篇
肿瘤学   76409篇
  2019年   11420篇
  2018年   16335篇
  2017年   12780篇
  2016年   14439篇
  2015年   15721篇
  2014年   21023篇
  2013年   32803篇
  2012年   44201篇
  2011年   47450篇
  2010年   27414篇
  2009年   25447篇
  2008年   45301篇
  2007年   48340篇
  2006年   47715篇
  2005年   46696篇
  2004年   44644篇
  2003年   43062篇
  2002年   41805篇
  2001年   60220篇
  2000年   62280篇
  1999年   51128篇
  1998年   14753篇
  1997年   13327篇
  1996年   13519篇
  1995年   12607篇
  1994年   11799篇
  1993年   11061篇
  1992年   38925篇
  1991年   38290篇
  1990年   36990篇
  1989年   35815篇
  1988年   33168篇
  1987年   32570篇
  1986年   31003篇
  1985年   29410篇
  1984年   22542篇
  1983年   19671篇
  1982年   11851篇
  1979年   21336篇
  1978年   15755篇
  1977年   13157篇
  1976年   12172篇
  1975年   13149篇
  1974年   15904篇
  1973年   15628篇
  1972年   14760篇
  1971年   13813篇
  1970年   13016篇
  1969年   12263篇
  1968年   11444篇
排序方式: 共有10000条查询结果,搜索用时 318 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