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   1077篇
  免费   67篇
  国内免费   12篇
耳鼻咽喉   1篇
儿科学   31篇
妇产科学   10篇
基础医学   73篇
口腔科学   58篇
临床医学   88篇
内科学   412篇
皮肤病学   29篇
神经病学   36篇
特种医学   109篇
外科学   120篇
综合类   66篇
预防医学   59篇
眼科学   8篇
药学   14篇
肿瘤学   42篇
  2023年   3篇
  2021年   14篇
  2020年   12篇
  2019年   5篇
  2018年   17篇
  2017年   12篇
  2016年   7篇
  2015年   19篇
  2014年   16篇
  2013年   31篇
  2012年   39篇
  2011年   53篇
  2010年   57篇
  2009年   48篇
  2008年   42篇
  2007年   58篇
  2006年   52篇
  2005年   46篇
  2004年   65篇
  2003年   40篇
  2002年   37篇
  2001年   39篇
  2000年   22篇
  1999年   29篇
  1998年   33篇
  1997年   30篇
  1996年   41篇
  1995年   23篇
  1994年   16篇
  1993年   21篇
  1992年   17篇
  1991年   15篇
  1990年   16篇
  1989年   21篇
  1988年   19篇
  1987年   19篇
  1986年   14篇
  1985年   15篇
  1984年   12篇
  1983年   15篇
  1982年   8篇
  1981年   13篇
  1980年   8篇
  1979年   2篇
  1978年   6篇
  1977年   8篇
  1976年   7篇
  1975年   4篇
  1973年   3篇
  1971年   2篇
排序方式: 共有1156条查询结果,搜索用时 15 毫秒
51.
52.
The aim of this study was to determine the effectiveness of uterine artery embolization (UAE) as a primary treatment method in treatment of symptomatic fibroids, whether there are any preembolization MRI characteristics of fibroid predictive of reduction in volume and assess reduction in uterine and dominant fibroid volumes using ultrasound (US) and MRI. Study was carried out in total of 32 patients aged 25–49 years (mean 40.9 years). Uterine and dominant fibroid volume were determined using US and MRI before UAE, MRI and US at 3 months and US alone at 6 and 12 months post‐UAE, supplemented by clinical evaluation at interval of 3, 6 and 12 months. Procedure was carried out through unilateral femoral puncture using poly vinyl alcohol (PVA) particles 355–500 μm in size. All 32 patients had successful procedures. Overall, 25 patients responded, giving a clinical success rate of 78.12%. Mean reduction in volume of uterus and fibroid was 33 and 59.7% and 48.9 and 75.5% on US at 3 and 12 months respectively, and 33.3 and 58.6% on MRI at 3 months. Volume reduction on US and MRI at 3 months was highly correlative. There was no statistical difference in size reduction in volume of fibroids, which were hypointense or hyperintense on T2‐weighted image (T2WI) on pre‐UAE MRI. Uterine artery embolization leads to good technical success and fibroid volume reduction. Ultrasound alone may be used for follow up of patients post‐UAE. Preprocedure signal characteristics on T2WI are not predictors of volume reduction after UAE.  相似文献   
53.
BACKGROUND: In the A-HeFT (African-American Heart Failure Trial), treatment of African-American patients with New York Heart Association (NYHA) class III/IV heart failure (HF) with fixed-dose combination (FDC) of isosorbide dinitrate/hydralazine (I/H) reduced mortality and morbidity and improved patient reported functional status compared with standard therapy alone. OBJECTIVE: To examine the benefit of FDC I/H in subgroups based on baseline drug therapy and to investigate whether ACE inhibitors and/or angiotensin receptor antagonists (angiotensin receptor blockers) [ARBs] or beta-adrenoceptor antagonists (beta-blockers) provided additional benefit in FDC I/H-treated African-American patients with HF. STUDY DESIGN: The A-HeFT was a double-blind, placebo-controlled study enrolling 1050 patients stabilized on optimal HF therapies and with NYHA class III/IV HF with systolic dysfunction conducted during the years 2001-4 with up to 18 months follow-up. The primary endpoint was a composite of mortality, first HF hospitalization, and improvement of quality of life at 6 months. Secondary endpoints included mortality, hospitalizations, and change in quality of life. Prospective Kaplan-Meier survival analyses were used for differences between FDC I/H and placebo groups and retrospective analyses were conducted within FDC I/H-treated and placebo groups. RESULTS: Subgroup analysis for mortality, event-free survival (death or first HF hospitalization), and HF hospitalization showed that FDC I/H, compared with placebo, was effective with or without ACE inhibitors or beta-blockers or other standard medications with all-point estimates favoring the FDC I/H group. Within the placebo-treated group, beta-blockers or ACE inhibitors and/or ARBs were efficacious in improving survival (hazard ratio [HR] 0.33; p<0.0001 for [beta]-blocker use and HR 0.39; p=0.01 for ACE inhibitor and/or ARB use). However, within the FDC I/H-treated group, use of beta-blockers, but not ACE inhibitors and/or ARBs, provided additional significant benefit for survival (HR 0.44; p=0.029 and HR 0.60; p=0.34, respectively), event-free survival (HR 0.62; p=0.034 and HR 0.72; p=0.29, respectively) and the composite score of death, HF hospitalization and change in quality of life (p=0.016 and p=0.13, respectively). CONCLUSION: Based on the analysis of baseline medication use in the A-HeFT, FDC I/H was superior to placebo with or without beta-blockers or ACE inhibitor. However, beta-blockers but not ACE inhibitors and/or ARBs provided additional significant benefit in African-Americans with HF treated with FDC I/H. These analyses are hypotheses generating and their confirmation in clinical trials needs to be considered.  相似文献   
54.
To our knowledge, placental transfer of pentamidine has not been previously studied in vivo. In the present study, the pharmacokinetics of pentamidine were analyzed in late gestation (18 days) among Sprague-Dawley rats. Pentamidine's kinetics were assessed in the following maternal compartments over a 12-hour period in 16 timed-pregnant rats: serum, liver, and kidney. Placentas were also analyzed for pentamidine concentration as were fetal brain, liver, and kidney tissues. Significant placental transfer of the drug was found, with pentamidine reaching all fetal compartments studied. Notably, by the twelfth hour fetal brain tissue achieved pentamidine concentrations that were not significantly different from those of maternal serum at the second hour of the experiment. This is an interesting observation because adult mouse and rat brains were found to be unexposed to the drug.  相似文献   
55.
In a prospective survey of infants born in a single maternity unit, asymptomatic faecal colonisation by Clostridium difficile occurred in 31 (47%) of 66 babies who provided a faecal sample during week one of life and at age 14 and 28 days, and in 46 (30.7%) of the total of 150 babies for whom at least one faecal sample was obtained during the month of study. There was no evidence for acquisition of the organism from the mother during delivery and colonisation was unrelated to the means of delivery, infant sex, means of feeding, duration of hospital stay, or antibiotic treatment. New colonisation occurred throughout the month of the study and further evidence for environmental acquisition was obtained by the finding of a similar strain of C difficile in 7 babies from one ward together with positive environmental cultures. Colonisation was frequently transient and occasionally intermittent; most infants kept the same strain during their period of carriage. Twenty two (47.8%) babies colonised by C difficile had low titres of cytopathic faecal toxin but none had symptomatic diarrhoea or features of necrotizing enterocolitis. The in vitro toxigenic potential of 57 toxigenic isolates from 36 babies was low and 12 babies carried non-toxigenic strains. Transient colonisation by C difficile in early life is almost certainly more common than is generally recognized and the neonate provides an important reservoir of potential infection.  相似文献   
56.
FOXM1 is a downstream target of Gli1 in basal cell carcinomas   总被引:10,自引:0,他引:10  
  相似文献   
57.
BACKGROUND: Prior studies have found associations between surgeon and hospital case volumes and outcomes after carotid endarterectomy (CEA), but they have not simultaneously assessed the importance of a number of surgeon and hospital characteristics. OBJECTIVE: To simultaneously assess associations between hospital case volume, teaching status, clinical trial participation, and surgeon specialty and case volume and the outcome after CEA. DESIGN: Analysis of a large administrative data-base using logistic regression to correlate adverse outcomes after CEA with surgeon and hospital characteristics. SETTING AND PATIENTS: A Canadian administrative hospital discharge database of all patients undergoing CEA in fiscal years 1994 through 1997. MAIN OUTCOME MEASURES: In-hospital stroke and/or death. RESULTS: We found an inverse relationship between both hospital and surgeon case volumes and adverse outcomes. Teaching status had no association with outcome, but previous clinical trial participation predicted a better outcome. General surgeons fared worse than other specialists. Low-volume surgeons in low-volume hospitals had a relative risk of 3.5 for adverse outcomes compared with high-volume surgeons in high-volume hospitals. CONCLUSIONS: Several physician and hospital characteristics are determinants of outcome after CEA, but the negative effects of low hospital and surgeon case volumes, in particular, suggest that regionalization should be considered for CEA and that surgeons with low case volumes should not be performing CEA.  相似文献   
58.
59.
60.
Interventional radiologic procedures in the renal transplant   总被引:1,自引:0,他引:1  
Percutaneous interventional procedures can be valuable in the evaluation and treatment of urologic complications of renal transplantation. Thirty-three patients underwent percutaneous procedures, including relief of obstruction by catheter nephrostomy, diagnostic antegrade pyelography with Whitaker testing, aspiration of various fluid collections (lymphocele, hematoma, urinoma, and abscess), and renal artery angioplasty, during a three year period at three institutions, to provide temporizing treatment and anatomic data. Surgical intervention was sometimes avoided, but more often it could be deferred to allow the patient to stabilize prior to surgery. Complications that required surgery occurred in two patients.  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