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   34730篇
  免费   2838篇
  国内免费   1236篇
耳鼻咽喉   96篇
儿科学   1003篇
妇产科学   129篇
基础医学   3247篇
口腔科学   333篇
临床医学   3873篇
内科学   12492篇
皮肤病学   161篇
神经病学   268篇
特种医学   1595篇
外科学   2871篇
综合类   5705篇
现状与发展   3篇
预防医学   1221篇
眼科学   137篇
药学   3269篇
  10篇
中国医学   2059篇
肿瘤学   332篇
  2024年   41篇
  2023年   509篇
  2022年   786篇
  2021年   1151篇
  2020年   1283篇
  2019年   1092篇
  2018年   1171篇
  2017年   1193篇
  2016年   1098篇
  2015年   1332篇
  2014年   2205篇
  2013年   2302篇
  2012年   2058篇
  2011年   2245篇
  2010年   1989篇
  2009年   2005篇
  2008年   2047篇
  2007年   2055篇
  2006年   1935篇
  2005年   1610篇
  2004年   1234篇
  2003年   1043篇
  2002年   895篇
  2001年   795篇
  2000年   651篇
  1999年   555篇
  1998年   448篇
  1997年   365篇
  1996年   293篇
  1995年   305篇
  1994年   274篇
  1993年   189篇
  1992年   180篇
  1991年   157篇
  1990年   150篇
  1989年   116篇
  1988年   112篇
  1987年   127篇
  1986年   96篇
  1985年   112篇
  1984年   91篇
  1983年   45篇
  1982年   84篇
  1981年   55篇
  1980年   52篇
  1979年   46篇
  1978年   54篇
  1977年   36篇
  1976年   42篇
  1975年   25篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
BackgroundIschemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat.MethodsRat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed.ResultsPre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators.ConclusionOur result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction.  相似文献   
2.
3.
4.
5.
von Willebrand factor (VWF) plays a crucial role in hemostasis and thrombosis. VWF is involved in platelet attachment to the subendothelium, serving as a carrier protein for coagulation factor VIII. In this study, myocardial tissues from deceased patients with ischemic heart disease and a mouse model of acute myocardial infarction were subjected to immunohistochemistry to determine VWF expression. We examined 28 neutral formalin-fixed, paraffin-embedded myocardial tissue samples obtained from the autopsies of patients who were diagnosed with ischemic heart disease within 48 h postmortem. Most myocardial cells were negative for VWF, although some cells showed nonspecific positivity. Elevated VWF expression was observed around myocardial cells undergoing remodeling, suggesting that endothelial proliferation occurred at these sites. In contrast, completely fibrotic myocardial foci did not show upregulated VWF expression. Positivity in fibrin deposition and hemorrhagic sites was observed. The same VWF expression characteristics as those observed in the human samples were observed in the mouse model. VWF immunostaining as an endothelial marker may be a useful supplementation to conventional staining techniques that are currently used in the diagnosis of ischemic heart disease in terms of examining the timing of myocardial remodeling in detail and highlighting the remodeling process.  相似文献   
6.
目的 通过分析特发性肺纤维化急性加重期(AE-IPF)患者证候与血清生物标志物的关系,为中医辨证治疗提供参考。方法 采用观察性研究设计,收集2019年3月至2019年11月三个中心的AE-IPF患者76例,其中痰热壅肺证26例、痰浊阻肺证50例,并纳入健康志愿者10例作为对照。采用ELISA测定患者血清CCL18、HMGB1、KL-6、MMP-7、SP-A和SP-D水平,分析与中医证候的相关性。结果 AE-IPF患者血清CCL18、HMGB1、KL-6、MMP-7、SP-A和SP-D水平均显著高于健康对照组。血清CCL18、HMGB1、KL-6、MMP-7和SP-D水平在痰热壅肺证和痰浊阻肺证患者间无显著性差异(P>0.05),而血清SP-A水平存在显著性差异(P<0.05)。结论 血清SP-A与AE-IPF证候存在一定的相关性,血清SP-A的浓度升高,与痰热壅肺证关系越密切,反之,血清SP-A浓度降低,则与痰浊阻肺证关系越密切。AE-IPF痰热壅肺证患者的预后可能较痰浊阻肺证患者更差。  相似文献   
7.
Objective: The objective of this study was to determine the efficacy of curcumin in combination with  intralesional dexamethasone with hyaluronidase in the treatment of oral submucous fibrosis (OSF). Methods: This randomized, double blind, parallel design, clinical trial was conducted at B.P. Koirala Institute of Health Sciences, Nepal. Thirty-four patients with clinically diagnosed OSF were randomized into two groups (17 participants in each) with baseline treatment of intralesional dexamethasone with hyaluronidase for 6 weeks for the both. Curcumin (2gm/day) was provided to Group A (Test) and Group B (Control) received placebo. Interincisal mouth opening, tongue protrusion, cheek flexibility and visual analogue scale (VAS) scoring of burning sensation of oral mucosa was recorded at baseline, 6, 8 and 12 weeks follow-up and independent t-test was used to compare the improvements in two groups. Results: On comparing the 6 weeks and baseline values, in Group A and B the mean difference in mouth opening was 8.82±1.33 mm and 5.53±1.17 mm respectively (p<0.001), in cheek flexibility was 2.94±1.02 mm and 1.94±1.24 mm respectively (p=0.02) and in tongue protrusion was 6.23±1.48 and 3.65±1.37 mm respectively (p<0.001). The findings were consistent in the 8 weeks follow-up. In 12 weeks follow-up, on comparing with the baseline values, in Group A and B, the mean difference in mouth opening was 8.71±1.16 mm and 5.35±1.22 mm respectively (<0.001), ), in cheek flexibility was 2.81±1.01 mm and 1.76±1.35 mm respectively (p=0.02) and in tongue protrusion was 6.06±1.48 and 3.35±1.50 mm respectively (p<0.001). Both the arms showed 100% improvement in burning sensation in 6, 8 and 12 weeks follow-up. Conclusion: Curcumin in combination with intralesional dexamethasone with hyaluronidase is efficacious in the treatment of OSF.  相似文献   
8.
目的 对中医药治疗特发性肺纤维化(idiopathic pulmonary fibrosis, IPF)的系统评价(SRs)进行再评价。方法 检索知网、中国生物医学数据库、维普、万方、The Cochrane Library、Web of Science、PubMed和EMbase数据库,纳入中医药治疗IPF的SRs,截止2021年5月。使用AMSTAR 2量表进行方法学质量评价,GRADE系统工具进行结局指标证据质量分级。结果 共纳入28篇文献,试验组除辨证论治外,治疗方法集中在活血化瘀、补肺益气等方面,基本符合治疗法则。结果显示中医药治疗IPF可以提高有效率、增加肺功能、提高PaO2、增加6WMD、缓解临床症状、提高患者的生活质量等。AMSTAR 2量表评价,所纳入SRs均有多项关键条目不达标,整体方法学质量等级不高。采用GRADE工具进行质量分级,一共234个结局指标,无高等证据质量,整体证据等级不高。结论 中医药对比西医治疗IPF有效且不良反应不明显,但RCT研究和系统评价研究方法质量尚有缺陷,完全按照西医评价指标可能会低估真实结果,未来需要更规范的研究及适合中医的评价指标,对中医药研究的安全性方面关注还有待提高。  相似文献   
9.
目的 研究蒙药安神补心六味丸对大鼠心肌缺血损伤的保护作用和氧化应激机制。方法 将60只大鼠随机分为空白组、模型组、阳性对照组(丹参滴丸)及蒙药安神补心六味丸低、中、高剂量组,使用腹腔注射异丙肾上腺素方法制备大鼠急性心肌缺血模型,记录并观察大鼠心电图活动变化,然后进行腹主动脉取血,分离血清,测定乳酸脱氢酶(Lactic dehydrogenase,LDH)、肌酸激酶(Creatine kinase,CK)、磷酸肌酸激酶(Creatine kinase isoenzyme,CK-MB)、谷草转氨酶(Aspartate aminotransferase,AST)、超氧化物歧化酶(Superoxide dismutase,SOD)、丙二醛(Malondialdehyde,MDA)和谷胱甘肽过氧化物酶(Glutathione peroxidase,GSH-PX)含量变化。取心肌组织固定,对大鼠心肌组织进行HE染色,通过对心肌酶学和和心肌组织形态学两个方面来考察蒙药安神补心六味丸对大鼠心肌缺血模型的保护作用。结果 与空白组比较,模型组大鼠血清中LDH活性极显著升高(P<0.01),CK、CK-MB、AST、MDA活性均显著升高(P<0.05),SOD活性显著降低(P<0.05),GSH-PX活性高度显著降低(P<0.001),且差异均具有统计学意义;与模型组比较,蒙药安神补心六味丸组高剂量组大鼠血清中LDH、CK、CK-MB、MDA活性显著降低(P<0.05),SOD活性显著升高(P<0.05),GSH-PX活性极显著升高(P<0.01),且差异均具有统计学意义。从HE染色分析,蒙药安神补心六味丸能够改善因缺血而造成的心肌组织损伤。结论 蒙药安神补心六味丸能有效改善心肌组织病理状态,减轻大鼠心肌缺血损伤,以达到保护心肌作用,机制可能与氧化应激机制相关。  相似文献   
10.
Elevated serum uric acid (SUA) levels have been associated with several cardiovascular risk factors and the progression of coronary artery disease. In the setting of acute myocardial infarction, increasing evidence suggests that high SUA levels could be related to adverse outcomes. Interestingly elevated SUA levels have been linked to endothelial dysfunction, inflammation and oxidative stress. The aim of this review is to discuss the potential negative effects of SUA in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention, analyzing the possible underlying pathophysiological mechanisms.  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