首页 | 官方网站   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   6331篇
  免费   469篇
  国内免费   32篇
医药卫生   6832篇
  2023年   31篇
  2022年   44篇
  2021年   173篇
  2020年   89篇
  2019年   161篇
  2018年   180篇
  2017年   104篇
  2016年   117篇
  2015年   179篇
  2014年   251篇
  2013年   298篇
  2012年   493篇
  2011年   478篇
  2010年   277篇
  2009年   253篇
  2008年   435篇
  2007年   441篇
  2006年   424篇
  2005年   444篇
  2004年   406篇
  2003年   404篇
  2002年   395篇
  2001年   59篇
  2000年   50篇
  1999年   84篇
  1998年   89篇
  1997年   58篇
  1996年   46篇
  1995年   49篇
  1994年   42篇
  1993年   18篇
  1992年   24篇
  1991年   22篇
  1990年   35篇
  1989年   25篇
  1988年   26篇
  1987年   19篇
  1986年   18篇
  1985年   10篇
  1984年   11篇
  1983年   8篇
  1982年   8篇
  1981年   4篇
  1979年   4篇
  1978年   4篇
  1975年   4篇
  1973年   7篇
  1972年   3篇
  1971年   6篇
  1966年   3篇
排序方式: 共有6832条查询结果,搜索用时 15 毫秒
61.
62.
Background/Aims: Alcoholic cirrhosis is the most common cause of liver transplantation in US males. The limited number of donor livers calls for“prioritisation”, favouring those patients who will benefit most. The aim was to assess the efficacy of liver transplantation in patients with alcoholic cirrhosis.Methods: We compared the survival of 169 transplantedpatients with two conservatively treated control groups, one of 169 patients matched for prognostic factors (age, cirrhosis severity, bleeding history) and one of 169 simulated patients.Results: The probability of survival to 5 years in the transplanted group was 66% (95% confidence interval 58–74%) vs 52% (44–60; p=0.03) in the matched group and 54% (51–57; p=0.01) in the simulated controls. Transplantation was associated with survival (relative RISK=1.51; p=0.02), independently of risk score (risk=2.07; p<0.001), indication, period of inclusion, centre experience, and alcohol abstinence. Patients with severe disease (Pugh C11–15) benefited most in terms of 5-year survival: 58% (44–72) vs 31% (17–45; p=0.008) in the matched and 35% (30–40; p<0.001) in the simulated control groups. For patients at lower risk there was no significant difference.Conclusions: Liver transplantation increases the 5-year survival of patients with severe alcoholic cirrhosis. In patients at lower risk, efficacy of transplantation should be confirmed by longer follow-up or by randomised trial.  相似文献   
63.

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   
64.
We hypothesized that patients with chronic obstructive pulmonary disease developing contractile fatigue of the quadriceps during cycle exercise may have characteristic metabolic and muscle features that could increase their susceptibility to fatigue, thus differentiating them from those who do not develop fatigue. We examined, in 32 patients, the fiber-type proportion, enzymatic activities, and capillary density in the vastus lateralis and the arterial blood lactate level during constant work-rate cycling exercise. Contractile fatigue was defined as a postexercise fall in quadriceps twitch force greater than 15% of resting values. Twenty-two patients developed contractile fatigue after exercise. No significant differences were found between fatiguers and non-fatiguers for the endurance time, fiber-type proportion, and oxidative enzyme activities. The lactate dehydrogenase activity was significantly higher (p < 0.05) and muscle capillarization significantly reduced in fatiguers (p < 0.05). Compared with non-fatiguers, the arterial lactate level during exercise was significantly higher in fatiguers (p < 0.001). A significant relationship was found between the fall in quadriceps twitch force and lactate dehydrogenase activity, capillary/fiber ratio, and blood lactate level. We conclude that changes in muscle enzymatic profile and capillarization with a greater reliance on glycolytic metabolism during exercise are associated with contractile fatigue in patients with chronic obstructive pulmonary disease.  相似文献   
65.

Introduction

Prothrombin complex concentrates (PCC) are haemostatic blood preparations indicated for urgent anticoagulation reversal, though the optimal dose for effective reversal is still under debate. The latest generation of PCCs include four coagulation factors, the so-called 4-factor PCC. The aim of this study was to compare the efficacy and safety of two doses, 25 and 40 IU/kg, of 4-factor PCC in vitamin K antagonist (VKA) associated intracranial haemorrhage.

Methods

We performed a phase III, prospective, randomised, open-label study including patients with objectively diagnosed VKA-associated intracranial haemorrhage between November 2008 and April 2011 in 22 centres in France. Patients were randomised to receive 25 or 40 IU/kg of 4-factor PCC. The primary endpoint was the international normalised ratio (INR) 10 minutes after the end of 4-factor PCC infusion. Secondary endpoints were changes in coagulation factors, global clinical outcomes and incidence of adverse events (AEs).

Results

A total of 59 patients were randomised: 29 in the 25 IU/kg and 30 in the 40 IU/kg group. Baseline demographics and clinical characteristics were comparable between the groups. The mean INR was significantly reduced to 1.2 - and ≤1.5 in all patients of both groups - 10 minutes after 4-factor PCC infusion. The INR in the 40 IU/kg group was significantly lower than in the 25 IU/kg group 10 minutes (P = 0.001), 1 hour (P = 0.001) and 3 hours (P = 0.02) after infusion. The 40 IU/kg dose was also effective in replacing coagulation factors such as PT (P = 0.038), FII (P = 0.001), FX (P <0.001), protein C (P = 0.002) and protein S (0.043), 10 minutes after infusion. However, no differences were found in haematoma volume or global clinical outcomes between the groups. Incidence of death and thrombotic events was similar between the groups.

Conclusions

Rapid infusion of both doses of 4-factor PCC achieved an INR of 1.5 or less in all patients with a lower INR observed in the 40 IU/kg group. No safety concerns were raised by the 40 IU/kg dose. Further trials are needed to evaluate the impact of the high dose of 4-factor PCC on functional outcomes and mortality.

Trial registration

Eudra CT number 2007-000602-73.  相似文献   
66.
67.
68.
69.
BACKGROUND: Small scale clinical trials suggested the feasibility and the efficacy of autologous myoblast transplantation to improve ventricular function after myocardial infarction. However, these trials were hampered by unexpected episodes of life-threatening ventricular tachyarrhythmias (VT). We investigated cardiac electrical stability after myoblast transplantation to the myocardium. METHODS AND RESULTS: Seven days after coronary ligation, Wistar rats were randomized into 3 groups: a control group receiving no further treatment, a vehicle group injected with culture medium into the infarcted myocardium, and a myoblast group injected with autologous myoblasts. Holter monitoring did not discriminate the myoblast from the vehicle groups. Programmed Electrical Stimulation (PES) was performed to evaluate further a cardiac substrate for arrhythmia susceptibility. The occurrence of sustained VT during PES was similar in control and vehicle groups (5/17 and 4/19 rats, respectively; p=0.50). In contrast, 13/20 rats (65%) from the myoblast group showed at least one episode of sustained VT during PES (p<0.05 and p<0.005 versus control and vehicle groups). As a further control group, rats injected with autologous bone marrow mononuclear cells into the infarcted myocardium did not show increased susceptibility to PES. CONCLUSIONS: In an infarcted rat model, myoblast transplantation but not bone marrow mononuclear cells or myocardial injection per se induces electrical ventricular instability. Because ventricular arrhythmias are life-threatening disorders, we suggest that such preclinical evaluation should be conducted for any new source of cells to be injected into the myocardium.  相似文献   
70.
BACKGROUND: Bartonella quintana, the etiological agent of bacillary angiomatosis (BA), causes endothelial cell proliferation. Erythromycin has dramatic effects on BA, and the effects are largely unexplained by the compound's bacteriostatic properties. Our aim here was to evaluate the possibility that erythromycin alters angiogenesis. METHODS: The effect of erythromycin on B. quintana-induced endothelial cell proliferation was studied using a wild-type strain and an erythromycin-resistant B. quintana mutant. The latter was generated by serial subcultures on blood agar plates. RESULTS: We show that erythromycin significantly inhibits the proliferation of dermal microvascular endothelial cells induced either by wild-type B. quintana or by our erythromycin-resistant mutant. Doxycycline and gentamycin failed to exert such an effect. Finally, we found that the resistant strain harbored a 27-bp insertion in the highly conserved region of the gene encoding the ribosomal protein L4; this insertion may explain the existence of the resistance to erythromycin. CONCLUSION: The data presented here indicate that erythromycin profoundly down-modulates endothelial cell proliferation irrespective of its bacteriostatic effects and suggest that this may be a key component of the efficacy of the compound in the treatment of patients with BA.  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-23

京公网安备 11010802026262号