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   2053020篇
  免费   152498篇
  国内免费   4955篇
耳鼻咽喉   27932篇
儿科学   61014篇
妇产科学   54718篇
基础医学   299430篇
口腔科学   59456篇
临床医学   187988篇
内科学   398294篇
皮肤病学   43411篇
神经病学   161982篇
特种医学   78269篇
外国民族医学   354篇
外科学   307264篇
综合类   46001篇
现状与发展   10篇
一般理论   782篇
预防医学   157156篇
眼科学   47046篇
药学   155978篇
  28篇
中国医学   5676篇
肿瘤学   117684篇
  2018年   21517篇
  2017年   16873篇
  2016年   18340篇
  2015年   21358篇
  2014年   29290篇
  2013年   43158篇
  2012年   58918篇
  2011年   62376篇
  2010年   36586篇
  2009年   34918篇
  2008年   59057篇
  2007年   62423篇
  2006年   62835篇
  2005年   61080篇
  2004年   58413篇
  2003年   56062篇
  2002年   54555篇
  2001年   100664篇
  2000年   103161篇
  1999年   86880篇
  1998年   22753篇
  1997年   20350篇
  1996年   20690篇
  1995年   19393篇
  1994年   18028篇
  1993年   16721篇
  1992年   67522篇
  1991年   65601篇
  1990年   63551篇
  1989年   61769篇
  1988年   56945篇
  1987年   55562篇
  1986年   52412篇
  1985年   49633篇
  1984年   36778篇
  1983年   31744篇
  1982年   17885篇
  1981年   15908篇
  1979年   34109篇
  1978年   24179篇
  1977年   20392篇
  1976年   18402篇
  1975年   20110篇
  1974年   24488篇
  1973年   23661篇
  1972年   22461篇
  1971年   21104篇
  1970年   19991篇
  1969年   18928篇
  1968年   17471篇
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
1.
Quality of Life Research - The COVID-19 pandemic might add to the stressors experienced by people living with rheumatic diseases. This study aimed to examine rheumatic patients’ functional...  相似文献   
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.
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