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   3429269篇
  免费   240852篇
  国内免费   8909篇
耳鼻咽喉   47670篇
儿科学   113454篇
妇产科学   96322篇
基础医学   484548篇
口腔科学   96004篇
临床医学   307155篇
内科学   670811篇
皮肤病学   80503篇
神经病学   277771篇
特种医学   131863篇
外国民族医学   1048篇
外科学   515476篇
综合类   69731篇
现状与发展   6篇
一般理论   1208篇
预防医学   263782篇
眼科学   78132篇
药学   252962篇
  9篇
中国医学   6940篇
肿瘤学   183635篇
  2018年   37911篇
  2017年   28710篇
  2016年   32961篇
  2015年   37247篇
  2014年   50933篇
  2013年   77034篇
  2012年   103427篇
  2011年   109711篇
  2010年   65721篇
  2009年   62368篇
  2008年   102662篇
  2007年   109524篇
  2006年   111426篇
  2005年   107302篇
  2004年   103255篇
  2003年   99757篇
  2002年   96805篇
  2001年   158794篇
  2000年   162847篇
  1999年   137598篇
  1998年   39915篇
  1997年   35360篇
  1996年   35617篇
  1995年   34259篇
  1994年   31688篇
  1993年   29728篇
  1992年   108390篇
  1991年   104999篇
  1990年   102283篇
  1989年   99099篇
  1988年   91271篇
  1987年   89628篇
  1986年   84577篇
  1985年   80839篇
  1984年   60082篇
  1983年   51553篇
  1982年   30715篇
  1981年   27276篇
  1979年   54554篇
  1978年   38467篇
  1977年   32961篇
  1976年   30767篇
  1975年   33182篇
  1974年   39131篇
  1973年   37347篇
  1972年   35387篇
  1971年   32777篇
  1970年   30638篇
  1969年   29411篇
  1968年   27275篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
Acute lung injury (ALI) caused by systemic inflammatory response remains a leading cause of morbidity and mortality in critically ill patients. Management of patients with sepsis is largely limited to supportive therapies, reflecting an incomplete understanding of the underlying pathophysiology. Furthermore, there have been limited advances in the treatments for ALI. In this study, lung function and a histological analysis were performed to evaluate the impact of transient receptor potential vanilloid‐1 receptor (TRPV1) antagonist (capsazepine; CPZ) on the lipopolysaccharide (LPS)‐induced lung injury in mice. For this, adult mice pre‐treated with CPZ or vehicle received intraperitoneal injections of LPS or saline and 24 hr after, the mice were anaesthetized, and lung mechanics was evaluated. The LPS‐challenged mice exhibited substantial mechanical impairment, characterized by increases in respiratory system resistance, respiratory system elastance, tissue damping and tissue elastance. The pre‐treatment with CPZ prevented the increase in respiratory system resistance and decreased the increase in tissue damping during endotoxemia. In addition, mice pre‐treated with CPZ had an attenuated lung injury evidenced by reduction on collapsed area of the lung parenchyma induced by LPS. This suggests that the TRPV1 antagonist capsazepine has a protective effect on lung mechanics in ALI during endotoxemia and that it may be a target for enhanced therapeutic efficacy in ALI.  相似文献   
63.
64.
65.
66.
Context Withania somnifera (L.) Dunal is traditionally used for treating various ailments, but lacks scientific evaluation.

Objective This study evaluates Withania somnifera (WS) for its effect on platelet activity and inflammatory enzymes.

Materials and methods Aqueous and ethanolic (1:1) leaf extracts were subjected to in vitro indirect haemolytic activity using Naja naja venom, human platelet aggregation was quantified for lipid peroxidation using arachidonic acid (AA) as agonist and 5-lipoxygenase (5-LOX) levels were determined using standard spectrometric assays. Further, molecular docking was performed by the ligand fit method using molegro software package (Molegro ApS, Aarhus, Denmark).

Results The study found that aqueous and ethanol extracts have very negligible effect (15%) with an IC50 value of 13.8?mg/mL on PLA2 from Naja naja venom. Further, extracts of WS also had very little effect (18%) with an IC50 value of 16.6?mg/mL on malondialdehyde (MDA) formation. However, a 65% inhibition of 5-LOX with an IC50 value of 0.92?mg/mL was observed in 1:1 ethanol extracts. The same was evident from SAR model with the active ingredient withaferin A binding predominantly on Phe 77, Tyr 98, Arg 99, Asp 164, Leu 168, Ser 382, Arg 395, Tyr 396 and Tyr 614 with an atomic contact energy value of??128.96 compared to standard phenidone (?103.61). Thus, the current study validates the application of WS for inflammatory diseases.

Conclusion This study reveals the inhibitory potential of W. somnifera on inflammatory enzymes and platelet aggregation. Thus, WS can serve as a newer, safer and affordable medicine for inflammatory diseases.  相似文献   
67.
68.
69.
70.
Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis.  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