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   244939篇
  免费   19527篇
  国内免费   7886篇
耳鼻咽喉   1560篇
儿科学   7971篇
妇产科学   1910篇
基础医学   23410篇
口腔科学   6420篇
临床医学   26517篇
内科学   57236篇
皮肤病学   3255篇
神经病学   26998篇
特种医学   7789篇
外国民族医学   12篇
外科学   21280篇
综合类   33873篇
一般理论   9篇
预防医学   17651篇
眼科学   2816篇
药学   16938篇
  193篇
中国医学   10959篇
肿瘤学   5555篇
  2024年   224篇
  2023年   4809篇
  2022年   6361篇
  2021年   11457篇
  2020年   12062篇
  2019年   8868篇
  2018年   8624篇
  2017年   9102篇
  2016年   9023篇
  2015年   8984篇
  2014年   17474篇
  2013年   19539篇
  2012年   14448篇
  2011年   15868篇
  2010年   12426篇
  2009年   12060篇
  2008年   12122篇
  2007年   11849篇
  2006年   10556篇
  2005年   8881篇
  2004年   7569篇
  2003年   6525篇
  2002年   5369篇
  2001年   4672篇
  2000年   3807篇
  1999年   3217篇
  1998年   2802篇
  1997年   2429篇
  1996年   2157篇
  1995年   2243篇
  1994年   2055篇
  1993年   1729篇
  1992年   1681篇
  1991年   1499篇
  1990年   1196篇
  1989年   1029篇
  1988年   970篇
  1987年   883篇
  1986年   758篇
  1985年   913篇
  1984年   753篇
  1983年   482篇
  1982年   572篇
  1981年   511篇
  1980年   404篇
  1979年   332篇
  1978年   255篇
  1977年   222篇
  1976年   210篇
  1975年   79篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
1.
目的 探讨不同时期慢性阻塞性肺疾病(COPD)患者血清诱饵受体3(DcR3)、凋亡抑制蛋白(Survivin)表达水平及临床意义。方法 选取2018年9月—2019年12月本院收治的92名COPD患者为研究对象,其中稳定型COPD 50例,急性加重期COPD 42例;同期本院健康体检者88例为对照组。测定各组研究对象血清DcR3、Survivin水平及肺功能指标。 与对照组[DcR3(106.54±48.35)pg/mL,Survivin(98.85±26.59)pg/mL]比较,稳定期组和急性加重期组血清DcR3[(395.23±123.85)pg/mL,(1 248.81±213.59)pg/mL]、Survivin [(267.54±84.69)pg/mL,(1 233.95±307.26)pg/mL]水平升高;与稳定期组比较,急性加重期组血清DcR3、Survivin水平升高。与对照组比较,稳定期组和急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001);与稳定期组比较,急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001)。随着低氧血症严重程度的增加,COPD患者血清DcR3、Survivin水平逐渐增加(P<0.001)。多因素logistics回归分析显示,高水平DcR3、Survivin、IL-12、hs-CRP为COPD病情的危险因素(P<0.001)。DcR3、Survivin与FEV、FEV1 /FVC呈负相关,与IL-12、TNF-α、hs-CRP呈正相关(P<0.001)。 COPD稳定期、急性加重期患者血清DcR3、Survivin表达水平升高,且DcR3、Survivin与COPD病情严重程度呈正相关。  相似文献   
2.
3.
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   
4.
IntroductionDetailed data on clinical characteristics in children with the omicron strain of SARS-COV-2 are limited.MethodsWe conducted a retrospective observational study of children with COVID-19 at the National Center for Child Health and Development to evaluate the clinical manifestations during and before the emergence of the omicron variant. Only symptomatic patients without underlying diseases were included. Participants were divided into two temporal groups: the “omicron era” (1/2022–2/2022) and the “pre-omicron era,” where the delta variant predominated (7/2021–11/2021). The patients were subclassified into an older vaccine-eligible group (aged 12–17 years), a younger vaccine-eligible group (aged 5–11 years), and a vaccine-ineligible group (aged 0–4 years).ResultsWe compared 113 patients in the omicron era with 106 in the pre-omicron era. Most patients in both eras had non-severe disease, and no patients required mechanical ventilation or died. Among patients aged 0–4 years, sore throat and hoarseness were more common during the omicron era than the pre-omicron era (11.1% vs. 0.0% and 11.1% vs. 1.5%, respectively). Croup syndrome was diagnosed in all patients with hoarseness. Among patients aged 5–11 years, vomiting was more frequent during the omicron era (47.2%) than during the pre-omicron era (21.7%). Cough and rhinorrhea were less common during the omicron era in patients aged 0–4 and 5–11 years, respectively, than during the pre-omicron era.ConclusionsIn children with COVID-19, clinical manifestations differed between the omicron and pre-omicron eras. In the Omicron era, croup syndrome was more frequent in vaccine-ineligible children.  相似文献   
5.
6.
IntroductionThe aim of this study was to compare long-term patient reported outcomes (PROs) in patients with locally advanced extremity soft tissue sarcoma (eSTS) after isolated limb perfusion followed by resection (IR), compared to extended resection (ER), primary amputation (A) or secondary amputation after IR (IR-A).MethodsPatients were selected from the respondents of a multi-institutional cross-sectional cohort survivorship study (SURVSARC) conducted among sarcoma survivors registered in the Netherlands Cancer Registry (NCR), 2–10 years after diagnosis. Used PROs were the EORTC QLQ-C30, the Cancer worry scale (CWS), the Hospital Anxiety and Depression Scale (HADS), and the Toronto Extremity Salvage Score (TESS).ResultsWe identified 97 eSTS survivors: IR = 20, ER = 49, A = 20, IR-A = 8. While there were no differences in PROs between IR and ER, results showed better functioning and functionality in both groups versus the amputation groups. The amputation groups scored significantly lower on physical functioning (A = 62.7, IR-A = 65.7 versus IR = 78.0, ER = 82.7, p = 0.001) and role functioning (A = 67.5, IR-A = 52.8 versus IR = 79.2, ER = 80.6, p = 0.039), both EORTC QLQ-C30 scales. Also for the TESS, the scores were significantly lower for the amputation groups compared to the limb sparing groups (upper extremity p = 0.007 with A = 68.9, IR-A = 71.6 versus IR = 93.3, ER = 91.1; lower extremity p < 0.001 with A = 72.2, IR-A50.9 versus IR = 84.5 and ER = 85.5). There were no significant differences between the groups on cancer worry, anxiety and depression.ConclusionHRQoL in eSTS survivors treated with IR or ER is equal; for maintenance of physical functioning and functionality IR and ER outperform an amputation.  相似文献   
7.
8.
9.
对间歇性禁食法的概念、方法及形式、历史发展以及在糖尿病前期及糖尿病病人中的应用效果等进行介绍,阐述间歇性禁食法研究现状,总结间歇性禁食法对糖尿病前期和糖尿病病人的有益影响。  相似文献   
10.
Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare life-threatening complication of blood transfusion caused by donor T cells that escape rejection by the recipient immune system. These donor T cells drive recipient tissue damage in response to host antigens. On the other hand, GVHD occurring after allogeneic hematopoietic cell transplantation (HCT-GVHD) is also caused by donor T cells, but its pathophysiology is more complex and differs due to the effects of tissue damage caused by pre?HCT conditioning and profound immunosuppression. Both TA-GVHD and HCT-GVHD can be fatal; however, mortality is higher with TA-GVHD due to the paucity of treatment options. Here, we compare and summarize the presentation, diagnosis, pathophysiology, prevention, and treatment of TA-GVHD and HCT-GVHD.  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