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   1774篇
  免费   100篇
  国内免费   15篇
耳鼻咽喉   8篇
儿科学   36篇
妇产科学   78篇
基础医学   182篇
口腔科学   31篇
临床医学   143篇
内科学   471篇
皮肤病学   29篇
神经病学   179篇
特种医学   44篇
外科学   231篇
综合类   4篇
预防医学   89篇
眼科学   16篇
药学   200篇
中国医学   7篇
肿瘤学   141篇
  2024年   2篇
  2023年   16篇
  2022年   37篇
  2021年   57篇
  2020年   33篇
  2019年   48篇
  2018年   54篇
  2017年   45篇
  2016年   49篇
  2015年   69篇
  2014年   73篇
  2013年   89篇
  2012年   148篇
  2011年   144篇
  2010年   75篇
  2009年   63篇
  2008年   107篇
  2007年   115篇
  2006年   108篇
  2005年   113篇
  2004年   78篇
  2003年   103篇
  2002年   79篇
  2001年   18篇
  2000年   20篇
  1999年   19篇
  1998年   17篇
  1997年   8篇
  1996年   11篇
  1995年   9篇
  1994年   4篇
  1993年   4篇
  1992年   15篇
  1991年   10篇
  1990年   4篇
  1989年   3篇
  1988年   8篇
  1987年   10篇
  1986年   6篇
  1985年   8篇
  1984年   3篇
  1983年   5篇
  1982年   1篇
  1964年   1篇
排序方式: 共有1889条查询结果,搜索用时 15 毫秒
81.
BACKGROUND: Relatively few data are available on long-term echocardiographic optimization of atrioventricular (AV) and interventricular (VV) delay programming in cardiac resynchronization therapy (CRT). We assessed variations in optimized AV and VV delays during long-term follow-up. METHODS: Thirty-seven consecutive heart failure patients received Doppler echocardiographic optimization of AV and VV delay within 48 hours from CRT device implantation, at 6 months and at 12 months (the last for the first enrolled 14 patients). RESULTS: After implantation, median optimized AV delay was 100 ms (range, 45 ms); VV optimization led to simultaneous biventricular activation in 4 patients, left ventricular preactivation in 17 patients and right ventricular preactivation in 16 patients. At 12 months median AV delay decreased to 85 ms (23 ms) (P < 0.05 vs. baseline). With respect to previous assessment, VV delay variations > or =40 ms were observed in 41% of the patients at 6 months and in 57% of the tested patients at 12 months. A nonconcordance (by Kappa test) of optimized VV delays was found between each new assessment and the previous one. VV delay optimization was associated with significant (P < 0.001) increases in aortic velocity time integral both at baseline and during follow-up. CONCLUSIONS: Echocardiographic optimization of AV and VV delay is associated with broad intraindividual variability during follow-up. A new assessment of optimized VV delays during long-term follow-up reveals a nonconcordance with previous values and provides increases in forward stroke volume.  相似文献   
82.
The objective of the present study is to test the use of a haemostatic sponge for urethral reconstructive surgery and to assess the relevant benefits. METHODS. The haemostatic sponge is made up of collagen with human fibrinogen and human thrombin. When the sponge gets in contact with fluids, such as blood, lymph or saline solution, the fibrinogen and thrombin are activated and form a fibrin net able to achieve local haemostasis and tissue regeneration. This kind of product was used in 30 selected patients (pts.), aged 19 - 70 (mean age: 35), who underwent single-stage anastomotic urethroplasty from January 2006 to March 2007: 22 bulbar end-to-end anastomoses and 8 bulbo- prostatic anastomoses. All operations were performed due to post-traumatic stricture of bulbar and posterior urethra. The main selection criterion for the use of the haemostatic sponge has always been the tendency to and/or the presence of bleeding in the different surgical stages. The sponge imbibed in saline solution and suitably modeled for all specific requirements was differently placed: sleeve-shaped in the case of bulbar anastomoses (16 pts.); as a "patch" in the centre of spongioplasty in bulbo-prostatic anastomoses (8 pts.), and within the widening incisions of the urethral roof performed between the two cavernous bodies at level of the intercrural septum (5 pts.). In 1 case (obese patient) a single sponge was placed after the deep perineal reconstruction on the bulbo-cavernous muscle- subcutaneous layers because of massive bleeding. RESULTS. In all cases a perfect control of haemostasis could be achieved, with immediate end of bleeding in the points where the haemostatic sponges were used. The dressings performed on day 3 upon removal of the compressive scrotum-perineal bandages did not show any late post-operative bleeding. The follow-up visits at month 1 and 3 yielded positive outcomes for all 30 patients, who achieved complete wound healing by first intention, and a perfect anastomosis especially in the bulbar end-to-end urethroplasty, confirmed by urethrografy at one month. CONCLUSIONS. The association of human fibrinogen and human thrombin in haemostatic sponges represents a manageable, useful product, apparently sure, not negatively interfering in repairing and regenerating tissue processes, and allowing a simple and direct control of important bleeding events occurring during urethral reconstructive surgery as well as other operations. It is therefore advisable to more widely use the product after a suitable followup period.  相似文献   
83.
84.

Objective

To conduct a systematic review to check the level of validity and reliability of the Manchester Triage System and the quality of reporting of literature on this topic.

Design

This is a systematic review based on the PRISMA guideline on reporting systematic reviews.

Data sources

The systematic search of the international literature published from 1997 through 30 November 2012 in the PubMed, Embase, Cochrane Library, Cinahl, Web of Knowledge, and Scopus databases.

Review methods

This review included quantitative and qualitative research investigating the reliability and validity of the Manchester Triage System for the broad population of adults and children visiting the emergency department.After a systematic selection process, included studies were assessed on their quality by three researchers using the STARD guidelines.

Results

Twelve studies were included in the review. The studies investigated the inter- and intra-rater reliability using the “kappa” statistic; the validity was tested with many measures: validity in predicting mortality, hospital admission, under- and overtriage, used resources, and length of stay in the emergency department, as well as a reference standard rating.

Conclusions

In this review, the Manchester Triage System shows a wide inter-rater agreement range with a prevalence of good and very good agreement. Its safety was low because of the high rate of undertriage and the low sensitivity in predicting higher urgency levels. The high rate of overtriage could cause unnecessarily high use of resources in the emergency department. The quality of the reporting in studies of the reliability and validity of the Manchester Triage System is good.  相似文献   
85.

Objectives

To evaluate maternal and fetal outcomes of multiple pregnancy according to route of delivery.

Material and methods

We performed a retrospective study of all twin deliveries in the previous 5 years and evaluated the route of delivery, especially in the final year. The information was recorded with Microsoft EXCEL and was analyzed with the statistical program SPSS 12.0 for Windows.

Results

The mean gestational age was 35.3 weeks. Route of delivery was through cesarean section in 59.8%. The mean interval between twins was 7.82 minutes when the first twin was delivered vaginally. Neonatal morbidity was found in 49%, and was higher in the second twin and in preterm deliveries.

Conclusions

Multiple pregnancies are associated with a large number of maternal and perinatal complications, as well as with a greater number of cesarean sections. Consequently, correct intrapartum management is required to reduce neonatal morbility as far as possible.  相似文献   
86.
87.
88.
Journal of Neurology - To unveil clinical features, comorbidities, disease progression and prognostic factors in a population-based cohort of ALS patients carrying C9ORF72 expansion...  相似文献   
89.
Human immunodeficiency virus (HIV)-associated progressive multifocal leukoencephalopathy (PML) remains a relevant clinical problem even in the era of highly active antiretroviral therapy (HAART). Aims of the study were to analyze clinical and treatment-related features and the survival probability of PML patients observed within the Italian Registry Investigative Neuro AIDS (IRINA) during a 29-month period of HAART. Intravenous drug use, the presence of focal signs, and the involvement of white matter at neuroradiology increased the risk of having PML. A reduced probability of PML was observed when meningeal signs were reported. Patients starting HAART at PML diagnosis and previously naïve for antiretrovirals showed significantly higher 1-year probability of survival (.58), compared to those continuing HAART (.24), or never receiving HAART (.00). Higher CD4 cell count were associated with a higher survival probability (.45). At multivariate analysis, a younger age, higher CD4, starting HAART at PML diagnosis, the absence of previous acquired immunodeficiency syndrome (AIDS)-defining events, and the absence of a severe neurologic impairment were all associated with a reduced hazard of death. The use of cidofovir showed a trend towards a reduced risk of death.  相似文献   
90.
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