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   102篇
  免费   6篇
  108篇
  2022年   2篇
  2021年   9篇
  2020年   1篇
  2019年   4篇
  2018年   2篇
  2016年   5篇
  2015年   7篇
  2014年   7篇
  2013年   4篇
  2012年   12篇
  2011年   7篇
  2010年   9篇
  2009年   6篇
  2008年   3篇
  2007年   3篇
  2006年   3篇
  2005年   6篇
  2003年   2篇
  2002年   4篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1987年   1篇
  1985年   2篇
  1984年   1篇
  1978年   1篇
排序方式: 共有108条查询结果,搜索用时 15 毫秒
51.
The latest generation of smartphones are increasingly viewed as handheld computers rather than as phones, due to their powerful on-board computing capability, capacious memories, large screens and open operating systems that encourage application development. This paper provides a brief state-of-the-art overview of health and healthcare smartphone apps (applications) on the market today, including emerging trends and market uptake. Platforms available today include Android, Apple iOS, RIM BlackBerry, Symbian, and Windows (Windows Mobile 6.x and the emerging Windows Phone 7 platform). The paper covers apps targeting both laypersons/patients and healthcare professionals in various scenarios, e.g., health, fitness and lifestyle education and management apps; ambient assisted living apps; continuing professional education tools; and apps for public health surveillance. Among the surveyed apps are those assisting in chronic disease management, whether as standalone apps or part of a BAN (Body Area Network) and remote server configuration. We describe in detail the development of a smartphone app within eCAALYX (Enhanced Complete Ambient Assisted Living Experiment, 2009-2012), an EU-funded project for older people with multiple chronic conditions. The eCAALYX Android smartphone app receives input from a BAN (a patient-wearable smart garment with wireless health sensors) and the GPS (Global Positioning System) location sensor in the smartphone, and communicates over the Internet with a remote server accessible by healthcare professionals who are in charge of the remote monitoring and management of the older patient with multiple chronic conditions. Finally, we briefly discuss barriers to adoption of health and healthcare smartphone apps (e.g., cost, network bandwidth and battery power efficiency, usability, privacy issues, etc.), as well as some workarounds to mitigate those barriers.  相似文献   
52.
Three near-infrared fluorescent heptacarbocyanine dyes have been synthesized using a facile one-pot synthetic approach. The reaction methodology afforded a mixture of three symmetric and unsymmetric heptacyanines containing various N-indolenine substituents, a dicarbocyclic acid (DA), a monoester (ME), and a diester (DE). These compounds were isolated, purified, characterized and biologically investigated for tumor cell cytotoxicity and uptake selectivity. Using cell viability and in vitro proliferation assays, we found that the esterified dyes (monoester, ME and diester, DE) were selectively cytotoxic to cancer cells and spared normal fibroblast cells. Additionally, confocal fluorescence imaging confirmed selective uptake of these dyes in cancer cells, thus suggesting tumor cell targeting.  相似文献   
53.

Background

Omega-3 long-chain (≥C20) polyunsaturated fatty acids (ω3 LC-PUFA) have critical roles in human health and development with studies indicating that deficiencies in these fatty acids can increase the risk or severity of cardiovascular and inflammatory diseases in particular. These fatty acids are predominantly sourced from fish and algal oils, but it is widely recognised that there is an urgent need for an alternative and sustainable source of EPA and DHA. Since the earliest demonstrations of ω3 LC-PUFA engineering there has been good progress in engineering the C20 EPA with seed fatty acid levels similar to that observed in bulk fish oil (∼18%), although undesirable ω6 PUFA levels have also remained high.

Methodology/Principal Findings

The transgenic seed production of the particularly important C22 DHA has been problematic with many attempts resulting in the accumulation of EPA/DPA, but only a few percent of DHA. This study describes the production of up to 15% of the C22 fatty acid DHA in Arabidopsis thaliana seed oil with a high ω3/ω6 ratio. This was achieved using a transgenic pathway to increase the C18 ALA which was then converted to DHA by a microalgal Δ6-desaturase pathway.

Conclusions/Significance

The amount of DHA described in this study exceeds the 12% level at which DHA is generally found in bulk fish oil. This is a breakthrough in the development of sustainable alternative sources of DHA as this technology should be applicable in oilseed crops. One hectare of a Brassica napus crop containing 12% DHA in seed oil would produce as much DHA as approximately 10,000 fish.  相似文献   
54.
Three prenylated flavonoid derivatives; 5,7,4′-trihydroxy-8-(3-methylbut-2-enyl)-6-(2″-hydroxy-3″-methylbut-3″enyl) isoflavone (isoerysenegalensein E), 5,7,2′-trihydroxy-4′-methoxy-5′-(3″-methylbut-2″-enyl) isoflavanone (lysisteisoflavanone), 5, 4′-dihydroxy-6-(3-methylbut-2-enyl)-2″-hydroxyisopropyl dihydrofurano [4″,5″:8,7] isoflavone (isosenegalensin), together with the four known flavonoids abyssinone V-4′-methylether, alpinumisoflavone, wighteone and burttinone were isolated from the stem bark of Erythrina lysistemon Hutch. (Leguminosae). Structures were elucidated by spectroscopic methods.  相似文献   
55.
56.
Given the significant low yield (19-43%) in reported results on the cyclocondensation of sulfaguanidine acetate with chalcones, a careful reinvestigation was carried out. A new series of chalcones, bearing electron-attracting groups in the aromatic moiety, have been used as precursors in the synthesis of diphenylsulfapyrimidine acetates with good yield. All synthesized compounds were active against G(+)- and G(-)-bacteria, and fungi. Combination of substituents (Cl, OMe, NO2, etc.) enhanced antimicrobial activity. Derivative with two NO2 groups exhibits an activity comparable with sulfadiazine.  相似文献   
57.
We have studied the effects of growth phase on the lipid composition in batch cultures of Gymnodinium sp. CS-380/3 over 43 days of culturing. The lipid content increased two fold, from late logarithmic (day 6) to linear growth phase (day 22) then decreased at stationary phase (day 43) while the lipid yield (mg l(-1)) increased 30-fold from day 6 to 30 mg l(-1) at day 43. Changes in fatty acid content mirrored those observed for the total lipid, while the sterol content continued to increase with culture age through to stationary phase. The largest changes occurred in the lipid classes, especially the polar lipids and triacylglycerols (oil). The proportion of triacylglycerols increased from 8% (of total lipids) at day 6 to 30% at day 43, with a concomitant decrease in the polar lipid fraction. The proportions of 16:0 and DHA [22:6(n-3)] increased while those of 18:5(n-3) and EPA [20:5(n-3)] decreased with increasing culture age. The proportion of the major sterol, dinosterol, decreased from 41% (day 6) to 29% (day 43), while the major dinostanol epimer (23R,24R) increased from 33% (day 6) to 38% (day 22). Despite small changes in the proportion of the main sterols, the same sterols were present at all stages of growth, indicating their value as a chemotaxonomic tool for distinguishing between strains within the same genus. Growth phase could be a useful variable for optimising the oil and DHA content with potential for aquaculture feeds and a source of DHA-rich oils for nutraceuticals.  相似文献   
58.
3-(1,1-Dioxadibenzothien-4-oyl)acrylic acid (1) was condensed with compounds containing active methylene groups under Michael reaction conditions to furnish the Michael adducts (lactones,2a–c, lactams,3a–c, ketones4a, b). The behavior of these adducts toward the action of hydrazine hydrate were investigated. The compounds were tested for their biological properties. 1st part of this series:Egypt. J. Chem. 42, 309 (1999).  相似文献   
59.
60.
Neurological disorders (NDs) are one of the leading causes of death especially in the developed countries. Among those NDs, Alzheimer’s disease (AD) and Parkinson disease (PD) are heading the table. There have been several reports in the scientific literatures which suggest the linkage between cardiovascular disorders (CVDs) and NDs. In the present communication, we have tried to compile NDs (AD and PD) association with CVDs reported in the literature. Based on the available scientific literature, we believe that further comprehensive study needs to be done to elucidate the molecular linking points associated with the above mentioned disorders.Abbreviations: AD, Alzheimer’s disease, Aβ, β amyloid, PD, Parkinson disease, l-DOPA, l-dihydroxyphenylalanine, LBs, Lewy bodies, DA, dopamine, APP, amyloid precursor protein, CVD, cardiovascular disease  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