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   206篇
  免费   13篇
工业技术   219篇
  2022年   3篇
  2021年   8篇
  2020年   12篇
  2019年   5篇
  2018年   8篇
  2017年   2篇
  2016年   9篇
  2015年   8篇
  2014年   11篇
  2013年   18篇
  2012年   11篇
  2011年   23篇
  2010年   16篇
  2009年   9篇
  2008年   7篇
  2007年   15篇
  2006年   3篇
  2005年   2篇
  2004年   3篇
  2003年   1篇
  2002年   4篇
  2001年   1篇
  2000年   2篇
  1999年   4篇
  1998年   9篇
  1997年   3篇
  1996年   2篇
  1995年   4篇
  1994年   3篇
  1993年   3篇
  1991年   2篇
  1989年   4篇
  1987年   2篇
  1982年   1篇
  1981年   1篇
排序方式: 共有219条查询结果,搜索用时 15 毫秒
131.
Mussel‐inspired polydopamine (PD) coating represents a promising route for constructing functional materials and finely tuning or completely changing their surface properties. In this work, a mild and effective method to realize the deposition of PD on keratin‐based films is reported. Reactive oxygen species (ROS), generated by keratin films doped with a photosensitizer, e.g., Azure A (AzA), upon UV–vis and vis‐near IR irradiation, are exploited to obtain the PD coating. Interestingly, the use of vis‐near IR irradiation leads to an increased production of ROS by AzA resulting in a greater PD deposition. Compared to uncoated keratin films, the PD‐keratin coated materials show a granular but homogeneous surface and an increased hydrophilicity, maintaining the ROS generation ability of AzA. This work demonstrates a useful method to effectively and rapidly functionalize with PD materials that are sensitive to temperature, pH and UV light, such as keratin. The proposed strategy allows obtaining new multifunctional biomaterials of potential interest in tissue engineering and drug delivery; in particular, the use of PD‐keratin films for near IR laser bonding of ophthalmic tissue, which is a representative case in wound healing purpose, is shown.  相似文献   
132.
133.
Titanium is one of the most frequently used materials in bone regeneration due to its good biocompatibility, excellent mechanical properties, and great osteogenic performance. However, osseointegration with host tissue is often not definite, which may cause implant failure at times. The present study investigates the capacity of the mesenchymal stem cell (MSC)-secretome, formulated as a ready-to-use and freeze-dried medicinal product (the Lyosecretome), to promote the osteoinductive and osteoconductive properties of titanium cages. In vitro tests were conducted using adipose tissue-derived MSCs seeded on titanium cages with or without Lyosecretome. After 14 days, in the presence of Lyosecretome, significant cell proliferation improvement was observed. Scanning electron microscopy revealed the cytocompatibility of titanium cages: the seeded MSCs showed a spread morphology and an initial formation of filopodia. After 7 days, in the presence of Lyosecretome, more frequent and complex cellular processes forming bridges across the porous surface of the scaffold were revealed. Also, after 14 and 28 days of culturing in osteogenic medium, the amount of mineralized matrix detected by alizarin red was significantly higher when Lyosecretome was used. Finally, improved osteogenesis with Lyosecretome was confirmed by confocal analysis after 28 and 56 days of treatment, and demonstrating the production by osteoblast-differentiated MSCs of osteocalcin, a specific bone matrix protein.  相似文献   
134.
The mevalonate pathway, crucial for cholesterol synthesis, plays a key role in multiple cellular processes. Deregulation of this pathway is also correlated with diminished protein prenylation, an important post-translational modification necessary to localize certain proteins, such as small GTPases, to membranes. Mevalonate pathway blockade has been linked to mitochondrial dysfunction: especially involving lower mitochondrial membrane potential and increased release of pro-apoptotic factors in cytosol. Furthermore a severe reduction of protein prenylation has also been associated with defective autophagy, possibly causing inflammasome activation and subsequent cell death. So, it is tempting to hypothesize a mechanism in which defective autophagy fails to remove damaged mitochondria, resulting in increased cell death. This mechanism could play a significant role in Mevalonate Kinase Deficiency, an autoinflammatory disease characterized by a defect in Mevalonate Kinase, a key enzyme of the mevalonate pathway. Patients carrying mutations in the MVK gene, encoding this enzyme, show increased inflammation and lower protein prenylation levels. This review aims at analysing the correlation between mevalonate pathway defects, mitochondrial dysfunction and defective autophagy, as well as inflammation, using Mevalonate Kinase Deficiency as a model to clarify the current pathogenetic hypothesis as the basis of the disease.  相似文献   
135.
136.
A precise 3D body scanning system, designed for applications in the medical and biomedical field, is described. The system consists of 12 digital cameras, mounted on a rigid frame which maintains the B/H ratio constant. An LED lighting system, integrated with the rigid frame, ensures a homogenous illumination of the subject. A modified firmware installed on each device enables the synchronised remote release driven by remote control. Data transmission to the computer is carried out wirelessly. A process for the estimation of the extrinsic camera parameters has been implemented with the aim of obtaining a 3D model in 1:1 scale. Analyses have been performed in order to state the repeatability of the process used to estimate the external camera calibration parameters as well as the precision of the 3D digital models of a body obtained for a mannequin and for a live human subject.  相似文献   
137.
Network function virtualization has enabled data center providers to offer new service provisioning models. Through the use of data center management software (cloud managers), providers allow their tenants to customize their virtual network infrastructure, enabling them to create a network topology that includes network functions (e.g., routers, firewalls), either chosen among the natively supported catalog or provided by third-parties. In order to deploy a ready-to-go service, providers have also to take care of pushing functional configurations into each network function (e.g., IP addresses for routers and policy rules in firewalls). This paper proposes an architecture that extends current cloud management software to enable the configuration of network functions. We propose a model-based approach that exploits the use of additional software components, i.e. translators and gateways, which are network function-agnostic, i.e. they are vendor-neutral and not specific for a particular type of network function, and do not require any change in the network functions. A prototype of this solution has been also implemented and tested, in order to validate our approach and evaluate its effectiveness in the configuration phase.  相似文献   
138.
Anthocyanins belong to the flavonoid group of polyphenolic compounds, which are responsible for the red and blue colors of plant organs such as fruits, flowers, and leaves. Due to their frequent presence in plants, particularly berry fruits, vegetables, and grapes, they are key components of the human diet. Interest in anthocyanins has increased widely during the past decade. Numerous studies have suggested that anthocyanins have a wide range of health‐promoting properties. These compounds are therefore considered to be a functional food factor, which may have important implications in the prevention of chronic diseases. The aim of this body of work is to investigate and review the current literature on anthocyanins, and particularly their pharmacokinetics and any health‐promoting properties, in order to summarize existing knowledge and highlight any aspects that require further study and analysis.  相似文献   
139.
140.
The purpose of the present study was to compare the end‐to‐end (ETEa) with the end‐to‐side (ETSa) anastomosis in patients starting hemodialysis by means of radio‐cephalic artero‐venous fistulae (AVF). In our experience, we compared the results, as early failure (EF), late thrombosis (LT), stenosis, steal syndrome, and primary patency (PP), in 2 groups of hemodialysis incident patients that had been placed an AVF by means of ETEa or ETSa. The observation period lasted 24 months for each of the 2 types of AVF, starting from October 2005 to September 2007 for ETEa and from October 2007 to September 2009 for ETSa. One hundred forty patients were included in the present study. We have consecutively performed 99 AVF interventions at the wrist or at the third distal of the forearm, in 70 patients by means of ETEa and 82 AVF interventions in the same anatomical places in 70 patients by means of ETSa. The patients with ETEa had a mean age of 64.4 ± 14.6 years, males were 65.8% and the age dialysis at the end of observation was 10.4 ± 5.7 months. Those with ETSa had a mean age of 65.9 ± 15.5 years and the males were 62.9%, the age dialysis at the end of observation was 9.2 ± 5.5 months. The surgical team was composed by the same nephrologists. The statistical study was performed by means of the χ chi‐square and Fisher's exact test. We have observed more late thrombosis (10% vs. 4.1%) and stenosis (21.4% vs. 2.7%) in ETEa than in ETSa. The number of early thrombosis was similar in the 2 types of anastomosis. The primary patency 1‐year rate was better though not significantly in the ETS (80% vs. 85.7%) In our experience the ETSa provides, overall better results, both regarding the complications and primary survival than ETEa. For the benefits that seem to come from it, we believe, that a broad ETSa in the distal native AVF is preferable to the ETEa.  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