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   20665篇
  免费   2615篇
  国内免费   374篇
耳鼻咽喉   127篇
儿科学   799篇
妇产科学   398篇
基础医学   1882篇
口腔科学   194篇
临床医学   2383篇
内科学   7189篇
皮肤病学   349篇
神经病学   1799篇
特种医学   344篇
外科学   2432篇
综合类   1312篇
现状与发展   1篇
一般理论   5篇
预防医学   1609篇
眼科学   715篇
药学   874篇
  2篇
中国医学   188篇
肿瘤学   1052篇
  2024年   55篇
  2023年   451篇
  2022年   258篇
  2021年   471篇
  2020年   440篇
  2019年   202篇
  2018年   776篇
  2017年   783篇
  2016年   846篇
  2015年   817篇
  2014年   747篇
  2013年   1019篇
  2012年   1466篇
  2011年   1490篇
  2010年   958篇
  2009年   923篇
  2008年   1288篇
  2007年   1233篇
  2006年   1070篇
  2005年   1186篇
  2004年   1503篇
  2003年   1309篇
  2002年   1006篇
  2001年   811篇
  2000年   304篇
  1999年   330篇
  1998年   373篇
  1997年   296篇
  1996年   141篇
  1995年   101篇
  1994年   86篇
  1993年   108篇
  1992年   90篇
  1991年   55篇
  1990年   61篇
  1989年   59篇
  1988年   56篇
  1987年   45篇
  1986年   39篇
  1985年   23篇
  1984年   20篇
  1983年   19篇
  1982年   20篇
  1981年   23篇
  1980年   14篇
  1977年   13篇
  1975年   13篇
  1974年   18篇
  1968年   17篇
  1928年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.

Background and objectives

Masked hypertension and elevated nighttime BP are associated with increased risk of hypertensive target organ damage and adverse cardiovascular and renal outcomes in patients with normal kidney function. The significance of masked hypertension for these risks in patients with CKD is less well defined. The objective of this study was to evaluate the association between masked hypertension and kidney function and markers of cardiovascular target organ damage, and to determine whether this relationship was consistent among those with and without elevated nighttime BP.

Design, setting, participants, & measurements

This was a cross-sectional study. We performed 24-hour ambulatory BP in 1492 men and women with CKD enrolled in the Chronic Renal Insufficiency Cohort Study. We categorized participants into controlled BP, white-coat, masked, and sustained hypertension on the basis of clinic and 24-hour ambulatory BP. We obtained echocardiograms and measured pulse wave velocity in 1278 and 1394 participants, respectively.

Results

The percentages of participants with controlled BP, white-coat, masked, and sustained hypertension were 49.3%, 4.1%, 27.8%, and 18.8%, respectively. Compared with controlled BP, masked hypertension independently associated with low eGFR (−3.2 ml/min per 1.73 m2; 95% confidence interval, −5.5 to −0.9), higher proteinuria (+0.9 unit higher in log2 urine protein; 95% confidence interval, 0.7 to 1.1), and higher left ventricular mass index (+2.52 g/m2.7; 95% confidence interval, 0.9 to 4.1), and pulse wave velocity (+0.92 m/s; 95% confidence interval, 0.5 to 1.3). Participants with masked hypertension had lower eGFR only in the presence of elevated nighttime BP (−3.6 ml/min per 1.73 m2; 95% confidence interval, −6.1 to −1.1; versus −1.4 ml/min per 1.73 m2; 95% confidence interval, −6.9 to 4.0, among those with nighttime BP <120/70 mmHg; P value for interaction with nighttime systolic BP 0.002).

Conclusions

Masked hypertension is common in patients with CKD and associated with lower eGFR, proteinuria, and cardiovascular target organ damage. In patients with CKD, ambulatory BP characterizes the relationship between BP and target organ damage better than BP measured in the clinic alone.  相似文献   
992.
993.
994.
995.
Little data are available on renal toxicity exerted by direct‐acting antivirals (DAAs) in real life. The aim of this study was to assess the impact of direct‐acting antivirals against hepatitis C virus infection currently used in Spain and Portugal on the estimated glomerular filtration rate (eGFR) in clinical practise. From an international, prospective multicohort study, patients treated with DAAs for at least 12 weeks and with eGFR ≥30 mL/min per 1.73 m2 at baseline were selected. eGFR was determined using the CKD‐EPI formula. A total of 1131 patients were included; 658 (58%) were HIV/HCV‐coinfected patients. Among the 901 patients treated for 12 weeks, median (interquartile range) eGFR was 100 (87‐107) at baseline vs 97 (85‐105) mL/min per 1.73 m2 at week 12 of follow‐up (FU12) post‐treatment (P < .001). For HIV‐coinfected subjects who received tenofovir plus a ritonavir‐boosted HIV protease inhibitor (PI/r), baseline vs FU12 eGFR were 104 (86‐109) vs 104 (91‐110) mL/min per 1.73 m2 (P = .913). Among subjects receiving ombitasvir/paritaprevir with or without dasabuvir, eGFR did not show any significant change. Of 1100 subjects with eGFR >60 mL/min per 1.73 m2 at baseline, 22 (2%) had eGFR <60 mL/min per 1.73 m2 at FU12, but none presented with eGFR <30 mL/min per 1.73 m2. In conclusion, eGFR slightly declines during therapy with all‐oral DAAs and this effect persists up to 12 weeks after stopping treatment in subjects with normal to moderately impaired renal function, regardless of HIV status. Concomitant use of tenofovir plus PI/r does not seem to have an impact on eGFR.  相似文献   
996.
997.

Background

Approximately 5 to 7% of patients undergoing percutaneous coronary intervention (PCI) for the treatment of coronary artery disease require chronic oral anticoagulation (OAC) on top of aspirin and a P2Y12 receptor antagonist, mainly due to non-valvular atrial fibrillation (AF). The advent of non-vitamin K antagonist oral anticoagulants (NOACs) increased treatment options, while there is cumulative evidence that dual combination of a NOAC and a P2Y12 receptor antagonist attenuates risk of bleeding, compared to traditional triple therapy, consisting of a vitamin K antagonist (VKA), aspirin, and a P2Y12 receptor antagonist, without significantly compromising efficacy.

Study Design

Greek AntiPlatElet Atrial Fibrillation (GRAPE-AF, NCT 03362788) is an observational, nationwide study of non-valvular AF patients undergoing PCI, planning to enroll over 1-year period >?500 participants in 25 tertiary and non-tertiary PCI centers in Greece. Key data to be collected pre-discharge include demographics, detailed past medical history, and antithrombotic and concomitant treatment. Patients will be followed up at 1, 6, and 12 months post hospital discharge. Αt each follow-up visit, data on antithrombotic treatment, ischemic, bleeding, and adverse events will be collected. Study’s primary endpoint is clinically significant bleeding (Bleeding Academic Research Consortium, BARC ≥?2) at 12 months, between VKAs and NOACs-treated patients, analyzed using Cox proportional hazards models, by an intention-to-treat principle. An independent endpoint committee will adjudicate all clinical events.

Conclusions

This study aims at providing “real-world” information on current antithrombotic treatment patterns and clinical outcome of patients with non-valvular AF undergoing PCI.
  相似文献   
998.

Objectives

The aim of this study was to determine the impact of food insecurity (FI) on HIV viral load and CD4 count among people coinfected with HIV and hepatitis C virus (HCV).

Methods

This study was conducted using data from the Food Security & HIV‐HCV Sub‐Study of the Canadian Co‐Infection Cohort study. FI was measured using the adult scale of Health Canada's Household Food Security Survey Module and was classified into three categories: food security, moderate food insecurity and severe food insecurity. The association between FI, HIV viral load, and CD4 count was assessed using a stabilized inverse probability weighted marginal structural model.

Results

A total of 725 HIV/HCV‐coinfected people with 1973 person‐visits over 3 years of follow‐up contributed to this study. At baseline, 23% of participants experienced moderate food insecurity and 34% experienced severe food insecurity. The proportion of people with undetectable HIV viral load was 75% and the median CD4 count was 460 [interquartile range (IQR): 300–665] cells/μL. People experiencing severe food insecurity had 1.47 times [95% confidence interval (CI): 1.14, 1.88] the risk of having detectable HIV viral load and a 0.91‐fold (95% CI: 0.84, 0.98) increase in CD4 count compared with people who were food secure.

Conclusions

These findings provide evidence of the negative impact of food insecurity on HIV viral load and CD4 count among HIV/HCV‐coinfected people.
  相似文献   
999.
1000.

Purpose

To test the effectiveness of a central venous catheter (CVC) insertion strategy and a hand hygiene (HH) improvement strategy to prevent central venous catheter-related bloodstream infections (CRBSI) in European intensive care units (ICUs), measuring both process and outcome indicators.

Methods

Adult ICUs from 14 hospitals in 11 European countries participated in this stepped-wedge cluster randomised controlled multicentre intervention study. After a 6 month baseline, three hospitals were randomised to one of three interventions every quarter: (1) CVC insertion strategy (CVCi); (2) HH promotion strategy (HHi); and (3) both interventions combined (COMBi). Primary outcome was prospective CRBSI incidence density. Secondary outcomes were a CVC insertion score and HH compliance.

Results

Overall 25,348 patients with 35,831 CVCs were included. CRBSI incidence density decreased from 2.4/1000 CVC-days at baseline to 0.9/1000 (p < 0.0001). When adjusted for patient and CVC characteristics all three interventions significantly reduced CRBSI incidence density. When additionally adjusted for the baseline decreasing trend, the HHi and COMBi arms were still effective. CVC insertion scores and HH compliance increased significantly with all three interventions.

Conclusions

This study demonstrates that multimodal prevention strategies aiming at improving CVC insertion practice and HH reduce CRBSI in diverse European ICUs. Compliance explained CRBSI reduction and future quality improvement studies should encourage measuring process indicators.
  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