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   4023984篇
  免费   285242篇
  国内免费   9071篇
耳鼻咽喉   55937篇
儿科学   131807篇
妇产科学   110690篇
基础医学   574057篇
口腔科学   112137篇
临床医学   370619篇
内科学   776519篇
皮肤病学   92947篇
神经病学   326344篇
特种医学   152322篇
外国民族医学   1141篇
外科学   600951篇
综合类   83733篇
现状与发展   15篇
一般理论   1665篇
预防医学   314975篇
眼科学   93702篇
药学   296400篇
  17篇
中国医学   7857篇
肿瘤学   214462篇
  2019年   32313篇
  2018年   44675篇
  2017年   33872篇
  2016年   38932篇
  2015年   43843篇
  2014年   61239篇
  2013年   92784篇
  2012年   125028篇
  2011年   132755篇
  2010年   79860篇
  2009年   75923篇
  2008年   124307篇
  2007年   132138篇
  2006年   134080篇
  2005年   129392篇
  2004年   124496篇
  2003年   119991篇
  2002年   116045篇
  2001年   183235篇
  2000年   188073篇
  1999年   159026篇
  1998年   47239篇
  1997年   41523篇
  1996年   41677篇
  1995年   40059篇
  1994年   36794篇
  1993年   34611篇
  1992年   124713篇
  1991年   120895篇
  1990年   117579篇
  1989年   113969篇
  1988年   104881篇
  1987年   102799篇
  1986年   96812篇
  1985年   92774篇
  1984年   69354篇
  1983年   59082篇
  1982年   35246篇
  1981年   31723篇
  1979年   62946篇
  1978年   44762篇
  1977年   37811篇
  1976年   35588篇
  1975年   38003篇
  1974年   45325篇
  1973年   43206篇
  1972年   40641篇
  1971年   38179篇
  1970年   35153篇
  1969年   33823篇
排序方式: 共有10000条查询结果,搜索用时 2 毫秒
31.

Introduction

In the United States there has been a large increase in participation in lacrosse for both males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.

Methods

We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.

Results

A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R2?=?0.823; p?=?0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R2?=?0.800; p?=?0.007), but again, there was no significance for female injury count (R2?=?0.417; p?=?0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the type of injury recorded.

Conclusion

The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency department.  相似文献   
32.
33.

Background

Chronic limb-threatening ischemia (CLTI), defined as ischemic rest pain or tissue loss secondary to arterial insufficiency, is caused by multilevel arterial disease with frequent, severe infrageniculate disease. The rise in CLTI is in part the result of increasing worldwide prevalence of diabetes, renal insufficiency, and advanced aging of the population. The aim of this study was to compare a bypass-first with an endovascular-first revascularization strategy in patients with CLTI due to infrageniculate arterial disease.

Methods

We reviewed the American College of Surgeons National Surgical Quality Improvement Program targeted lower extremity revascularization database from 2012 to 2015 to identify patients with CLTI and isolated infrageniculate arterial disease who underwent primary infrageniculate bypass or endovascular intervention. We excluded patients with a history of ipsilateral revascularization and proximal interventions. The end points were major adverse limb event (MALE), major adverse cardiovascular event (MACE), amputation at 30 days, reintervention, patency, and mortality. Multivariable logistic regression was used to determine the association of a bypass-first or an endovascular-first intervention with outcomes.

Results

There were 1355 CLTI patients undergoing first-time revascularization to the infrageniculate arteries (821 endovascular-first revascularizations and 534 bypass-first revascularizations) identified. There was no significant difference in adjusted rate of 30-day MALE in the bypass-first vs endovascular-first revascularization cohort (9% vs 11.2%; odds ratio [OR], 0.73; 95% confidence interval [CI], 0.50-1.08). However, the incidence of transtibial or proximal amputation was lower in the bypass-first cohort (4.3% vs 7.4%; OR, 0.60; CI, 0.36-0.98). Patients with bypass-first revascularization had higher wound complication rates (9.7% vs 3.7%; OR, 2.75; CI, 1.71-4.42) compared with patients in the endovascular-first cohort. Compared with the endovascular-first cohort, the incidence of 30-day MACE was significantly higher in bypass-first patients (6.9% vs 2.6%; adjusted OR, 3.88; CI, 2.18-6.88), and 30-day mortality rates were 3.23% vs 1.8% (adjusted OR, 2.77; CI, 1.26-6.11). There was no difference in 30-day untreated loss of patency, reintervention of treated arterial segment, readmissions, and reoperations between the two cohorts. In subgroup analysis after exclusion of dialysis patients, there was also no significant difference in MALE or amputation between the bypass-first and endovascular-first cohorts.

Conclusions

CLTI patients with isolated infrageniculate arterial disease treated by a bypass-first approach have a significantly lower 30-day amputation. However, this benefit was not observed when dialysis patients were excluded. The bypass-first cohort had a higher incidence of MACE compared with an endovascular-first strategy. These results reaffirm the need for randomized controlled trials, such as the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL-2) trial and Best Endovascular vs Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI), to provide level 1 evidence for the role of endovascular-first vs bypass-first revascularization strategies in the treatment of this population of challenging patients.  相似文献   
34.
According to the current nutritional recommendations issued by professional diabetes and nutrition associations, diabetic patients should keep to a diet consisting of 45–60% carbohydrates, 10–20% protein, and not more than 35% fat. However, not all of these nutritional recommendations are evidence based. For example, current studies show that the intake of insoluble roughage may be underrepresented. It is also possible that diabetic patients could benefit from keeping to the lower end of the recommended range for carbohydrates (45%) and the upper end of the range advised for protein (20%).  相似文献   
35.
36.
Zusammenfassung In Deutschland leiden 25% der über 70-Jährigen unter einem Diabetes mellitus. Biologisch ältere, multimorbide und in ihren Funktionen beeinträchtigte geriatrische Patienten benötigen spezielle Vorgehensweisen bei Zielplanung, Allgemeinmaßnahmen und Pharmakotherapie. Auf der Basis der vorhandenen Leitlinien werden gesicherte Erkenntnisse dargestellt und Empfehlungen zu den Besonderheiten der Therapie des geriatrischen Diabetespatienten gegeben. Besonderes Augenmerk liegt dabei auf der Interaktion von geriatrischen Syndromen und Diabetes sowie der Verbesserung der Lebensqualität.  相似文献   
37.
We report the case of a littoral‐cell angioma of the spleen, a recently described benign vascular tumour, whose imaging and pathological characteristics have been discussed only by a few authors. The diagnosis was made after elective splenectomy. The CT images, scintigraphy and histological specimens are presented, and differential diagnoses discussed.  相似文献   
38.
39.
Bernard–Soulier syndrome (BSS) is a rare autosomal recessively inherited bleeding disorder. Pregnancy in patients with BSS is characterized by ante‐, intra‐, or postpartum haemorrhage, which may be delayed and severe. There is no consensus in the management of BSS in pregnancy and so far only 16 pregnancies in nine patients have been described. We report a further three pregnancies in two women with the syndrome. We also outline our management of pregnant patients with BSS.  相似文献   
40.
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