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   1167篇
  免费   102篇
  国内免费   4篇
医药卫生   1273篇
  2024年   2篇
  2023年   13篇
  2022年   32篇
  2021年   57篇
  2020年   32篇
  2019年   55篇
  2018年   68篇
  2017年   62篇
  2016年   55篇
  2015年   64篇
  2014年   71篇
  2013年   87篇
  2012年   111篇
  2011年   110篇
  2010年   75篇
  2009年   37篇
  2008年   66篇
  2007年   65篇
  2006年   53篇
  2005年   39篇
  2004年   42篇
  2003年   26篇
  2002年   15篇
  2001年   6篇
  2000年   3篇
  1999年   4篇
  1998年   5篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1994年   4篇
  1992年   3篇
  1988年   2篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
排序方式: 共有1273条查询结果,搜索用时 78 毫秒
11.
12.
13.
With the successful uptake and inclusion of robotic systems in minimally invasive surgery and with the increasing application of robotic surgery (RS) in numerous surgical specialities worldwide, there is now a need to develop and enhance the technology further. One such improvement is the implementation and amalgamation of haptic feedback technology into RS which will permit the operating surgeon on the console to receive haptic information on the type of tissue being operated on. The main advantage of using this is to allow the operating surgeon to feel and control the amount of force applied to different tissues during surgery thus minimising the risk of tissue damage due to both the direct and indirect effects of excessive tissue force or tension being applied during RS. We performed a two-rater systematic review to identify the latest developments and potential avenues of improving technology in the application and implementation of haptic feedback technology to the operating surgeon on the console during RS. This review provides a summary of technological enhancements in RS, considering different stages of work, from proof of concept to cadaver tissue testing, surgery in animals, and finally real implementation in surgical practice. We identify that at the time of this review, while there is a unanimous agreement regarding need for haptic and tactile feedback, there are no solutions or products available that address this need. There is a scope and need for new developments in haptic augmentation for robot-mediated surgery with the aim of improving patient care and robotic surgical technology further.  相似文献   
14.
Journal of Neurology - To report the understanding and decision-making of neuroimmunologists and their treatment of patients with multiple sclerosis (MS) during the early stages of the SARS-CoV-2...  相似文献   
15.
The development of regenerative therapies for cartilage injury has been greatly aided by recent advances in stem cell biology. Induced pluripotent stem cells (iPSCs) have the potential to provide an abundant cell source for tissue engineering, as well as generating patient-matched in vitro models to study genetic and environmental factors in cartilage repair and osteoarthritis. However, both cell therapy and modeling approaches require a purified and uniformly differentiated cell population to predictably recapitulate the physiological characteristics of cartilage. Here, iPSCs derived from adult mouse fibroblasts were chondrogenically differentiated and purified by type II collagen (Col2)-driven green fluorescent protein (GFP) expression. Col2 and aggrecan gene expression levels were significantly up-regulated in GFP+ cells compared with GFP− cells and decreased with monolayer expansion. An in vitro cartilage defect model was used to demonstrate integrative repair by GFP+ cells seeded in agarose, supporting their potential use in cartilage therapies. In chondrogenic pellet culture, cells synthesized cartilage-specific matrix as indicated by high levels of glycosaminoglycans and type II collagen and low levels of type I and type X collagen. The feasibility of cell expansion after initial differentiation was illustrated by homogenous matrix deposition in pellets from twice-passaged GFP+ cells. Finally, atomic force microscopy analysis showed increased microscale elastic moduli associated with collagen alignment at the periphery of pellets, mimicking zonal variation in native cartilage. This study demonstrates the potential use of iPSCs for cartilage defect repair and for creating tissue models of cartilage that can be matched to specific genetic backgrounds.  相似文献   
16.
17.
Cyclic neutropenia is a rare immunodeficiency syndrome, characterized by regular periodic oscillations in the circulating neutrophil count from normal to neutropenic levels through 3 weeks period, and lasting for 3-6 days. In order to determine the clinical features of cyclic neutropenia, this study was performed. Seven patients with cyclic neutropenia (3 males and 4 females), who experienced neutropenic periods every 3 weeks (5 with severe and 2 with moderate neutropenia), were investigated in this study. They had been referred to Iranian Primary Immunodeficiency Registry during 23 years (1980-2003). The range of patients' ages was from 7 to 13 years (median 11 years). The median age at the onset of the disease was 12 months (1 month- 2 years) and the median age of diagnosis was 2 (1.5-5) years, with a median diagnosis delay of 1 year (2 months- 5 years). Neutropenia was associated with leukopenia (3 patients), anemia (3 patients), and thrombocytopenia (1 patient). Patients were asymptomatic in healthy phase, but during the episode of neutropenia suffered from aphthous ulcers, abscesses and overwhelming infections. The most commonly occurred manifestations were: otitis media (6 cases), oral ulcers (5 cases), abscesses (4 cases), pneumonia (3 cases), diarrhea (3 cases), oral candidiasis (3 cases), cutaneous infections (2 cases), and periodontitis (2 cases). One of these patients subsequently died because of recurrent infections. Unusual, persistent or severe infections should be the initiating factors to search for an immune deficiency syndrome such as cyclic neutropenia, because a delay in diagnosis may result in chronic infection, irretrievable end-organ damage or even death of the patient.  相似文献   
18.

Background

The objective of this randomized, double-blind, placebo-controlled study was to evaluate the efficacy of sustained-release methylphenidate (MPH-SR) in treatment of methamphetamine dependence.

Methods

Fifty-six individuals who met DSM-IV-TR criteria for methamphetamine dependence participated in this 10-week trial. The participants were randomly allocated into two groups and received 18 to 54 mg/day sustained-released methylphenidate or placebo for 10 weeks. Craving was evaluated by a visual analogue craving scale every week. Urinary screening test for methamphetamine was carried out each week. The Beck Depression Inventory-II (BDI-II) was used to monitor participant depressive symptoms at baseline and bi-weekly during the treatment period.

Results

At the end of the trial, the MPH-SR group was less methamphetamine positive compared to the placebo group and the difference was significant (p = 0.03). By the end of the study, MPH-SR group showed significantly less craving scores compared to the placebo group [MD (95% CI) = -10.28(0.88-19.18), t(54) = 2.19, p = 0.03]. There was greater improvement in the depressive symptoms scores in the intervention group compared to the placebo group [MD (95% CI) =2.03(0.31-3.75), t (54) =2.37, p = 0.02].

Conclusion

Sustained-released methylphenidate was safe and well tolerated among active methamphetamine users and significantly reduced methamphetamine use, craving and depressive symptoms.

Trial registration

IRCT201202281556N38  相似文献   
19.
OBJECTIVES: The role of atrial myocytes and extracellular matrix (ECM) changes in atrial chamber remodeling was studied in a canine model of heart failure (HF). BACKGROUND: Cardiac remodeling is a key process mediating the progression of HF. Studies of the structural mechanisms of cardiac remodeling have been limited to the left ventricle. The structural alterations associated with atrial chamber remodeling in evolving HF have not been studied. METHODS: Age- and weight-matched dogs were subjected to right ventricular pacing (240 beats/min) for one and three weeks to produce early and severe HF, respectively. Atrial tissues were assessed for myocyte and ECM changes. RESULTS: Right atrial and left atrial (LA) pressures were significantly increased in early and severe HF. The LA wall tension index was significantly increased at both HF stages by 116% and 443%, respectively. Atrial collagen synthesis and degradation were significantly increased in severe HF. Gelatinase activity was significantly increased at both early and severe stages of HF. Gelatin zymography showed increased matrix metalloproteinases (MMP)-9 with early HF and increased MMP-2 with severe HF. The LA wall tension index was significantly correlated with gelatinase activity and collagen synthesis. Although total atrial collagen content was not changed, disarray of collagen fibers was observed. Atrial myocyte hypertrophy without evidence of apoptosis was also present in severe HF. CONCLUSIONS: There is marked atrial chamber remodeling in canine pacing-induced HF, which is characterized by myocyte hypertrophy and dynamic collagen turnover. Atrial remodeling may contribute to the development of atrial arrhythmias and pulmonary hypertension and could offer a novel therapeutic target.  相似文献   
20.

Background:

Tertiary pediatric hospitals usually provide excellent clinical services, but such centers have a lot to do for educational perfection.

Objectives:

This study was performed to address under-graduate educational deficits and find feasible solutions.

Patients and Methods:

This cross-sectional study was done in a target population of 77 sixth year undergraduate medical students (response rate = 78%) who spent their 3-month pediatric rotation in the Children’s Medical Center, the Pediatrics Center of Excellence in Tehran, Iran. The Dundee ready educational environment measure (DREEM) instrument was used for assessing educational environment of this subspecialized pediatric hospital.

Results:

Among 60 students who answered the questionnaires, 24 were male (40%). Participants’ age ranged from 23 to 24 years. The mean total score was 95.8 (48%). Comparison of scores based on students’ knowledge showed no significant difference. Problematic areas were learning, academic self-perception, and social self-perception.

Conclusions:

Having an accurate schedule to train general practitioner, using new teaching methods, and providing a non-stressful atmosphere were suggested solutions.  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