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   2727篇
  免费   127篇
  国内免费   24篇
耳鼻咽喉   79篇
儿科学   181篇
妇产科学   169篇
基础医学   178篇
口腔科学   161篇
临床医学   184篇
内科学   477篇
皮肤病学   58篇
神经病学   256篇
特种医学   89篇
外科学   741篇
综合类   25篇
一般理论   1篇
预防医学   46篇
眼科学   63篇
药学   81篇
肿瘤学   89篇
  2024年   2篇
  2023年   27篇
  2022年   50篇
  2021年   108篇
  2020年   78篇
  2019年   89篇
  2018年   106篇
  2017年   97篇
  2016年   126篇
  2015年   146篇
  2014年   142篇
  2013年   169篇
  2012年   230篇
  2011年   225篇
  2010年   121篇
  2009年   109篇
  2008年   169篇
  2007年   186篇
  2006年   167篇
  2005年   132篇
  2004年   99篇
  2003年   66篇
  2002年   83篇
  2001年   25篇
  2000年   31篇
  1999年   20篇
  1998年   8篇
  1997年   10篇
  1996年   6篇
  1995年   14篇
  1994年   3篇
  1993年   5篇
  1992年   8篇
  1991年   4篇
  1990年   4篇
  1989年   2篇
  1988年   2篇
  1987年   3篇
  1986年   3篇
  1985年   1篇
  1984年   2篇
排序方式: 共有2878条查询结果,搜索用时 390 毫秒
91.
Myocardial metastasis from oesophageal cancer is very rare, and is usually detected as part of widespread metastases in the terminal stage. It is rare to detect a solitary metastasis. We present a case of solitary myocardial metastasis from distal oesophagus complicated by ventricular fibrillation.  相似文献   
92.

Introduction

The primary goal of this study was to compare the chest wall thicknesses (CWT) at the 2nd intercostal space (ICS) at the mid-clavicular line (MCL) and 5th ICS at the mid-axillary line (MAL) in a population of patients with a CT confirmed pneumothorax (PTX). This result will help physicians to determine the optimum needle thoracostomy (NT) puncture site in patients with a PTX.

Materials and methods

All trauma patients who presented consecutively to A&E over a 12-month period were included. Among all the trauma patients with a chest CT (4204 patients), 160 were included in the final analysis. CWTs were measured at both sides and were compared in all subgroup of patients.

Results

The average CWT for men on the 2nd ICS-MCL was 38 mm and for women was 52 mm; on the other hand, on the 5th ICS-MAL was 33 mm for men and 38 mm for women. On the 2nd ICS-MCL 17% of men and 48% of women; on the 5th ICS-MAL 13% of men and 33% of women would be inaccessible with a routine 5-cm catheter. Patients with trauma, subcutaneous emphysema and multiple rib fractures would have thicker CWT on the 2nd ICS-MCL. Patients with trauma, lung contusion, sternum fracture, subcutaneous emphysema and multiple rib fractures would have thicker CWT on the 5th ICS-MAL.

Conclusions

This study confirms that a 5.0-cm catheter would be unlikely to access the pleural space in at least 1/3 of female and 1/10 of male Turkish trauma patients, regardless of the puncture site. If NT is needed, the 5th ICS-MAL is a better option for a puncture site with thinner CWT.  相似文献   
93.
94.
95.
Little information exists regarding the efficacy, modifiers, and outcomes of anemia management in children with CKD or ESRD. We assessed practices, effectors, and outcomes of anemia management in 1394 pediatric patients undergoing peritoneal dialysis (PD) who were prospectively followed in 30 countries. We noted that 25% of patients had hemoglobin levels below target (<10 g/dl or <9.5 g/dl in children older or younger than 2 years, respectively), with significant regional variation; levels were highest in North America and Europe and lowest in Asia and Turkey. Low hemoglobin levels were associated with low urine output, low serum albumin, high parathyroid hormone, high ferritin, and the use of bioincompatible PD fluid. Erythropoiesis-stimulating agents (ESAs) were prescribed to 92% of patients, and neither the type of ESA nor the dosing interval appeared to affect efficacy. The weekly ESA dose inversely correlated with age when scaled to weight but did not correlate with age when normalized to body surface area. ESA sensitivity was positively associated with residual diuresis and serum albumin and inversely associated with serum parathyroid hormone and ferritin. The prevalence of hypertension and left ventricular hypertrophy increased with the degree of anemia. Patient survival was positively associated with achieved hemoglobin and serum albumin and was inversely associated with ESA dose. In conclusion, control of anemia in children receiving long-term PD varies by region. ESA requirements are independent of age when dose is scaled to body surface area, and ESA resistance is associated with inflammation, fluid retention, and hyperparathyroidism. Anemia and high ESA dose requirements independently predict mortality.Almost three decades after the advent of recombinant erythropoietin, the management of renal anemia has become a recent focus of attention and changing paradigms. Whereas correction of hemoglobin (Hb) levels to near-normal has previously been recommended on the basis of association studies linking more severe anemia to morbidity and mortality with dialysis,13 interventional clinical trials consistently demonstrate that near-normalization of Hb increases the risk of vascular events and mortality in adults receiving maintenance hemodialysis and in those with CKD who are not undergoing dialysis.46 This has prompted ongoing reevaluation and revisions of treatment targets in patients exposed to erythropoiesis-stimulating agents (ESAs).7The appropriateness of applying treatment recommendations established in adult hemodialysis populations at high cardiovascular risk and adults with CKD to children undergoing dialysis is questionable because cardiovascular events are far less common in children with CKD. Furthermore, two thirds of children requiring dialysis initially opt for peritoneal dialysis (PD), and there are no systematic studies in the adult PD population to inform the optimal Hb target range in these patients. The risk profile of patients receiving PD may differ from that of the hemodialysis setting because of the absence of dialysis-induced intermittent hemoconcentration and lack of contact activation of the complement and coagulation systems.Further aspects to consider in pediatric anemia management are the greater physical activity of children and the need for optimal cognitive functioning at school.8,9 The significant physiologic variation of the normal Hb range with age10 and the relative ESA sensitivity that reportedly increases with age during early childhood are also noteworthy.11The registry of the International Pediatric Peritoneal Dialysis Network (IPPN) prospectively collects detailed clinical, biochemical, dialysis, and medication-related information (including ESA types and doses and modalities of iron supplementation) from a substantial number of children undergoing long-term PD around the world. In-depth analysis of this unique database has allowed us to (1) gain insight into the demographic characteristics of renal anemia and its treatment in the pediatric PD population worldwide, (2) explore the relationship between ESA dose requirements and body dimensions, (3) identify factors contributing to ESA resistance in children, and (4) associate anemia control with patient outcomes.  相似文献   
96.

Background

The purpose of the present study was to determine the prevalence of diabetes and its effect on surgical outcomes in patients undergoing emergent, in-patient cholecystectomy for acute cholecystitis. Some 8.3 % of the U.S. population has diabetes and this number is projected to rise to 21–33 % by 2050. Diabetes is considered to be associated with a higher incidence of acute cholecystitis; however, its impact on outcomes is unknown.

Methods

The American College of Surgeons National Surgical Quality Improvement Program database was queried to identify all patients with acute cholecystitis who underwent emergent in-patient cholecystectomy from 2004 to 2010. The study population was divided into two groups: diabetics and non-diabetics. Diabetics were further subdivided into those taking oral medication and those on insulin. Demographics, co-morbidities, and wound classification were compared with univariate analysis, and 30-day outcomes were compared with univariate and multivariate analyses.

Results

A total of 5,460 patients met the inclusion criteria. Of these 770 (14.10 %) had a diagnosis of diabetes. Mortality was higher for diabetics than for non-diabetics [4.4 vs 1.4 %, adjusted odds ratio (AOR) (95 % CI): 1.79 (1.09, 2.94), adj-p = 0.022]. Preoperative perforation rates were 25.1 and 13.0 %, respectively [AOR (95 % CI): 1.34 (1.09, 1.65), adj-p = 0.005]. The adjusted risk of cardiovascular events and renal failure was significantly higher for diabetics. Insulin treatment, but not oral medication, was associated with a significant increase in mortality, preoperative perforation, superficial surgical site infection, septic shock, cardiovascular incidents, and renal insufficiency.

Conclusions

In patients undergoing cholecystectomy for acute cholecystitis, diabetes increases the risk of mortality, cardiovascular events, and renal failure. Insulin-treated diabetics have more co-morbidities and poorer outcomes.  相似文献   
97.
98.
99.
Background: The aim of this study is to evaluate CD4+, CD8+, and CD45RO+ T cells, and vascular endothelial growth factor (VEGF) expression in cyclosporin A (CsA)–induced rat overgrown gingival tissue during an 8‐week period. Methods: Sixty male Sprague‐Dawley rats weighing 200 to 250 g were used in this study. Mandibular first molars were ligated with 3–0 silk suture. The rats received daily doses of 0.09% NaCl (control group) or 10 mg/kg body weight of CsA (test group) by intraperitoneal injections. Five rats from the control group and 10 rats from the test group were sacrificed at each experimental period (2, 4, 6, and 8 weeks after the beginning of CsA treatment). The specimens were examined immunohistochemically. Results: CD4+, CD8+, and CD45RO+ T cells, and VEGF expression were more prevalent in the CsA‐treated group than in the control group (P <0.05). VEGF was significantly correlated with CD4+ T cells, CD4+/CD8+ ratio, and CD45RO+ cells (P <0.05). Conclusion: Based on our findings, we conclude that VEGF, a major regulator of angiogenesis, and CD4+, CD8+, and CD45RO+ memory T cells play a key role in CsA‐induced gingival overgrowth.  相似文献   
100.
Background and purposeIn continuation of our previous experimental study on spinal cord injury (SCI) using fetal stem cells, we investigated here the effects of fetal allogeneic umbilical cord tissue transplant on the urinary bladder morphology in a rat SCI model.Material and methodsFive pregnant albino Wistar rats at 12 days of gestation were used to obtain the umbilical cord cell graft. In Group 1 (n = 5), Th8-Th9 laminectomy was performed. Group 2 (n = 5) received spinal cord injury. In Group 3 (n = 5), the cultured fetal umbilical cord cells coated with alginate gel were placed into the lesion cavity. In Group 4 (n = 5), only alginate sponges without umbilical cord cells were placed into the injury cavity. The bladders of animals were analyzed pathologically at 21 days after surgery.ResultsThe thickness of the epithelium and the lamina propria did not differ among studied groups (p > 0.05). The lamina muscularis thickness was significantly higher in Group 2 and Group 4 than the others (p < 0.05). The bladder weight was similar among Groups 1, 2, and 3 (p > 0.05). Fibrosis was significantly increased in Group 2 (p < 0.05); it was greater in Group 2 than in Group 3 (p < 0.05) but did not differ between Groups 1 and 3 (p > 0.05).ConclusionsThis study suggests that allogeneic umbilical cord tissue transplantation after SCI may prevent bladder wall hypertrophy and fibrosis in the rat SCI model.  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