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   2223篇
  免费   130篇
  国内免费   2篇
耳鼻咽喉   63篇
儿科学   107篇
妇产科学   41篇
基础医学   192篇
口腔科学   19篇
临床医学   149篇
内科学   549篇
皮肤病学   31篇
神经病学   138篇
特种医学   66篇
外科学   402篇
综合类   25篇
预防医学   86篇
眼科学   111篇
药学   127篇
中国医学   1篇
肿瘤学   248篇
  2023年   17篇
  2022年   17篇
  2021年   94篇
  2020年   45篇
  2019年   85篇
  2018年   99篇
  2017年   50篇
  2016年   61篇
  2015年   68篇
  2014年   110篇
  2013年   123篇
  2012年   179篇
  2011年   161篇
  2010年   80篇
  2009年   85篇
  2008年   148篇
  2007年   126篇
  2006年   105篇
  2005年   98篇
  2004年   80篇
  2003年   62篇
  2002年   50篇
  2001年   38篇
  2000年   37篇
  1999年   41篇
  1998年   8篇
  1997年   6篇
  1996年   5篇
  1995年   9篇
  1994年   11篇
  1993年   6篇
  1992年   31篇
  1991年   24篇
  1990年   21篇
  1989年   22篇
  1988年   27篇
  1987年   22篇
  1986年   11篇
  1985年   14篇
  1984年   6篇
  1983年   5篇
  1979年   4篇
  1978年   5篇
  1976年   5篇
  1974年   6篇
  1973年   6篇
  1972年   6篇
  1970年   7篇
  1968年   5篇
  1961年   3篇
排序方式: 共有2355条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.

Background

There are conflicting data regarding the relative effectiveness of renal sympathetic denervation (RSD) in patients with hypertension.

Objectives

The purpose of this study was to evaluate the blood pressure (BP) response after RSD in sham-controlled randomized trials.

Methods

Databases were searched through June 30, 2018. Randomized trials (RCTs) with ≥50 patients comparing catheter-based RSD with a sham control were included. The authors calculated summary treatment estimates as weighted mean differences (WMD) with 95% confidence intervals (CIs) using random-effects meta-analysis.

Results

The analysis included 977 patients from 6 trials. The reduction in 24-h ambulatory systolic blood pressure (ASBP) was significantly greater for patients treated with RSD than sham procedure (WMD ?3.65 mm Hg, 95% CI: ?5.33 to ?1.98; p < 0.001). Compared with sham, RSD was also associated with a significant decrease in daytime ASBP (WMD ?4.07 mm Hg, 95% CI: ?6.46 to ?1.68; p < 0.001), office systolic BP (WMD ?5.53 mm Hg, 95% CI: ?8.18 to ?2.87; p < 0.001), 24-h ambulatory diastolic BP (WMD ?1.71 mm Hg, 95% CI: ?3.06 to ?0.35; p = 0.01), daytime ambulatory diastolic BP (WMD ?1.57 mm Hg, 95% CI: ?2.73 to ?0.42; p = 0.008), and office diastolic BP (WMD ?3.37 mm Hg, 95% CI: ?4.86 to ?1.88; p < 0.001). Compared with first-generation trials, a significantly greater reduction in daytime ASBP was observed with RSD in second-generation trials (6.12 mm Hg vs. 2.14 mm Hg; p interaction = 0.04); however, this interaction was not significant for 24-h ASBP (4.85 mm Hg vs. 2.23 mm Hg; p interaction = 0.13).

Conclusions

RSD significantly reduced blood pressure compared with sham control. Results of this meta-analysis should inform the design of larger, pivotal trials to evaluate the long-term efficacy and safety of RSD in patients with hypertension.  相似文献   
5.
6.
Infections and graft-versus-host disease (GVHD) have historically resulted in high mortality among children undergoing umbilical cord blood transplantation (UCBT). However, recent advances in clinical practice have likely improved outcomes of these patients. We conducted a retrospective cohort study of children (<18years of age) undergoing UCBT at Duke University between January 1, 1995 and December 31, 2014. We compared 2-year all-cause and cause-specific mortality during 3 time periods based on year of transplantation (1995 to 2001, 2002 to 2007, and 2008 to 2014). We used multivariable Cox regression to identify demographic and UCBT characteristics that were associated with all-cause mortality, transplantation-related mortality, and death from invasive aspergillosis after adjustment for time period. During the 20-year study period 824 children underwent UCBT. Two-year all-cause mortality declined from 48% in 1995 to 2001 to 30% in 2008 to 2014 (P?=?.0002). White race and nonmalignant UCBT indications were associated with lower mortality. Black children tended to have a higher risk of death for which GVHD (18% versus 11%; P?=?.06) or graft failure (9% versus 3%; P?=?.01) were contributory than white children. Comparing 2008 to 2014 with 1995 to 2001, more than half (59%) of the reduced mortality was attributable to a reduction in infectious mortality, with 45% specifically related to reduced mortality from invasive aspergillosis. Antifungal prophylaxis with voriconazole was associated with lower mortality from invasive aspergillosis than low-dose amphotericin B lipid complex (hazard ratio, .09; 95% confidence interval, .01 to .76). With the decline in mortality from invasive aspergillosis, adenovirus and cytomegalovirus have become the most frequentinfectious causes of death in children after UCBT. Advances in clinical practice over the past 20years improved survival of children after UCBT. Reduced mortality from infections, particularly invasive aspergillosis, accounted for the largest improvement in survival and was associated with use of voriconazole for antifungal prophylaxis.  相似文献   
7.
8.
9.
Urinary biomarkers of AKI provide prognostic value for in-hospital outcomes, but little is known about their association with longer-term mortality after surgery. We sought to assess the association between kidney injury biomarkers and all-cause mortality in an international, multicenter, prospective long-term follow-up study from six clinical centers in the United States and Canada composed of 1199 adults who underwent cardiac surgery between 2007 and 2009 and were enrolled in the Translational Research in Biomarker Endpoints in AKI cohort. On postoperative days 1–3, we measured the following five urinary biomarkers: neutrophil gelatinase-associated lipocalin, IL-18, kidney injury molecule-1 (KIM-1), liver fatty acid binding protein, and albumin. During a median follow-up of 3.0 years (interquartile range, 2.2–3.6 years), 139 participants died (55 deaths per 1000 person-years). Among patients with clinical AKI, the highest tertiles of peak urinary neutrophil gelatinase-associated lipocalin, IL-18, KIM-1, liver fatty acid binding protein, and albumin associated independently with a 2.0- to 3.2-fold increased risk for mortality compared with the lowest tertiles. In patients without clinical AKI, the highest tertiles of peak IL-18 and KIM-1 also associated independently with long-term mortality (adjusted hazard ratios [95% confidence intervals] of 1.2 [1.0 to 1.5] and 1.8 [1.4 to 2.3] for IL-18 and KIM-1, respectively), and yielded continuous net reclassification improvements of 0.26 and 0.37, respectively, for the prediction of 3-year mortality. In conclusion, urinary biomarkers of kidney injury, particularly IL-18 and KIM-1, in the immediate postoperative period provide additional prognostic information for 3-year mortality risk in patients with and without clinical AKI.In many studies, the development of AKI, defined by acute changes in serum creatinine, associates with a higher risk of long-term mortality.1,2 Acute changes in serum creatinine, however, may not fully reflect the severity of kidney injury due to the influence of age, sex, muscle mass, changes in hydration, nutritional status, and medications on creatinine kinetics. Moreover, serum creatinine may abruptly rise in hospitalized settings due to functional processes such as altered hemodynamics, without any true nephron damage. Several urinary biomarkers of structural kidney injury have been investigated in human cohorts in an effort to identify AKI earlier, improve the diagnosis of AKI, and to aid in risk stratification.3 It is largely unknown, however, whether kidney injury biomarkers associate with long-term outcomes, including mortality, and whether these biomarkers add useful prognostic information beyond the standard measure to detect AKI (e.g., peak change in serum creatinine). Some data suggest that “subclinical AKI,” as evidenced by elevations in urinary kidney injury biomarkers in the absence of a rise in serum creatinine, associates with worse in-hospital clinical outcomes.4 Few studies have examined whether kidney injury biomarkers associate with long-term mortality after hospital discharge.5To address the current knowledge gaps, we conducted this study to characterize the association between kidney injury biomarkers and long-term mortality and to assess whether these biomarkers provide any incremental prognostic information for long-term mortality beyond that of serum creatinine changes and other clinical variables.  相似文献   
10.
Main pancreatic duct (MPD) involvement is a well-demonstrated risk factor for malignancy in intraductal papillary mucinous neoplasm (IPMN). Preoperative radiographic determination of IPMN type is heavily relied upon in oncologic risk stratification. We hypothesized that radiographic assessment of MPD involvement in IPMN is an accurate predictor of pathological MPD involvement. Data regarding all patients undergoing resection for IPMN at a single academic institution between 1992 and 2012 were gathered prospectively. Retrospective analysis of imaging and pathologic data was undertaken. Preoperative classification of IPMN type was based on cross-sectional imaging (MRI/magnetic resonance cholangiopancreatography (MRCP) and/or CT). Three hundred sixty-two patients underwent resection for IPMN. Of these, 334 had complete data for analysis. Of 164 suspected branch duct (BD) IPMN, 34 (20.7 %) demonstrated MPD involvement on final pathology. Of 170 patients with suspicion of MPD involvement, 50 (29.4 %) demonstrated no MPD involvement. Of 34 patients with suspected BD-IPMN who were found to have MPD involvement on pathology, 10 (29.4 %) had invasive carcinoma. Alternatively, 2/50 (4 %) of the patients with suspected MPD involvement who ultimately had isolated BD-IPMN demonstrated invasive carcinoma. Preoperative radiographic IPMN type did not correlate with final pathology in 25 % of the patients. In addition, risk of invasive carcinoma correlates with pathologic presence of MPD involvement.  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