全文获取类型
收费全文 | 1684篇 |
免费 | 89篇 |
国内免费 | 1篇 |
出版年
2024年 | 4篇 |
2023年 | 22篇 |
2022年 | 46篇 |
2021年 | 82篇 |
2020年 | 45篇 |
2019年 | 58篇 |
2018年 | 63篇 |
2017年 | 35篇 |
2016年 | 74篇 |
2015年 | 85篇 |
2014年 | 88篇 |
2013年 | 128篇 |
2012年 | 129篇 |
2011年 | 133篇 |
2010年 | 73篇 |
2009年 | 59篇 |
2008年 | 78篇 |
2007年 | 82篇 |
2006年 | 65篇 |
2005年 | 64篇 |
2004年 | 66篇 |
2003年 | 53篇 |
2002年 | 48篇 |
2001年 | 13篇 |
2000年 | 8篇 |
1999年 | 15篇 |
1998年 | 12篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1968年 | 3篇 |
排序方式: 共有1774条查询结果,搜索用时 62 毫秒
71.
Petra S. Meier John Holmes Colin Angus Abdallah K. Ally Yang Meng Alan Brennan 《PLoS medicine》2016,13(2)
Introduction
While evidence that alcohol pricing policies reduce alcohol-related health harm is robust, and alcohol taxation increases are a WHO “best buy” intervention, there is a lack of research comparing the scale and distribution across society of health impacts arising from alternative tax and price policy options. The aim of this study is to test whether four common alcohol taxation and pricing strategies differ in their impact on health inequalities.Methods and Findings
An econometric epidemiological model was built with England 2014/2015 as the setting. Four pricing strategies implemented on top of the current tax were equalised to give the same 4.3% population-wide reduction in total alcohol-related mortality: current tax increase, a 13.4% all-product duty increase under the current UK system; a value-based tax, a 4.0% ad valorem tax based on product price; a strength-based tax, a volumetric tax of £0.22 per UK alcohol unit (= 8 g of ethanol); and minimum unit pricing, a minimum price threshold of £0.50 per unit, below which alcohol cannot be sold. Model inputs were calculated by combining data from representative household surveys on alcohol purchasing and consumption, administrative and healthcare data on 43 alcohol-attributable diseases, and published price elasticities and relative risk functions. Outcomes were annual per capita consumption, consumer spending, and alcohol-related deaths. Uncertainty was assessed via partial probabilistic sensitivity analysis (PSA) and scenario analysis.The pricing strategies differ as to how effects are distributed across the population, and, from a public health perspective, heavy drinkers in routine/manual occupations are a key group as they are at greatest risk of health harm from their drinking. Strength-based taxation and minimum unit pricing would have greater effects on mortality among drinkers in routine/manual occupations (particularly for heavy drinkers, where the estimated policy effects on mortality rates are as follows: current tax increase, −3.2%; value-based tax, −2.9%; strength-based tax, −6.1%; minimum unit pricing, −7.8%) and lesser impacts among drinkers in professional/managerial occupations (for heavy drinkers: current tax increase, −1.3%; value-based tax, −1.4%; strength-based tax, +0.2%; minimum unit pricing, +0.8%). Results from the PSA give slightly greater mean effects for both the routine/manual (current tax increase, −3.6% [95% uncertainty interval (UI) −6.1%, −0.6%]; value-based tax, −3.3% [UI −5.1%, −1.7%]; strength-based tax, −7.5% [UI −13.7%, −3.9%]; minimum unit pricing, −10.3% [UI −10.3%, −7.0%]) and professional/managerial occupation groups (current tax increase, −1.8% [UI −4.7%, +1.6%]; value-based tax, −1.9% [UI −3.6%, +0.4%]; strength-based tax, −0.8% [UI −6.9%, +4.0%]; minimum unit pricing, −0.7% [UI −5.6%, +3.6%]). Impacts of price changes on moderate drinkers were small regardless of income or socioeconomic group. Analysis of uncertainty shows that the relative effectiveness of the four policies is fairly stable, although uncertainty in the absolute scale of effects exists. Volumetric taxation and minimum unit pricing consistently outperform increasing the current tax or adding an ad valorem tax in terms of reducing mortality among the heaviest drinkers and reducing alcohol-related health inequalities (e.g., in the routine/manual occupation group, volumetric taxation reduces deaths more than increasing the current tax in 26 out of 30 probabilistic runs, minimum unit pricing reduces deaths more than volumetric tax in 21 out of 30 runs, and minimum unit pricing reduces deaths more than increasing the current tax in 30 out of 30 runs). Study limitations include reducing model complexity by not considering a largely ineffective ban on below-tax alcohol sales, special duty rates covering only small shares of the market, and the impact of tax fraud or retailer non-compliance with minimum unit prices.Conclusions
Our model estimates that, compared to tax increases under the current system or introducing taxation based on product value, alcohol-content-based taxation or minimum unit pricing would lead to larger reductions in health inequalities across income groups. We also estimate that alcohol-content-based taxation and minimum unit pricing would have the largest impact on harmful drinking, with minimal effects on those drinking in moderation. 相似文献72.
73.
Emilie Vessières Abdallah Dib Jennifer Bourreau Eric Lelièvre Marc-Antoine Custaud Martine Lelièvre-Pégorier Laurent Loufrani Daniel Henrion Céline Fassot 《PloS one》2016,11(1)
Epidemiologic studies have demonstrated that cardiovascular risk is not only determined by conventional risk factors in adulthood, but also by early life events which may reprogram vascular function. To evaluate the effect of maternal diabetes on fetal programming of vascular tone in offspring and its evolution during adulthood, we investigated vascular reactivity of third order mesenteric arteries from diabetic mother offspring (DMO) and control mother offspring (CMO) aged 3 and 18 months. In arteries isolated from DMO the relaxation induced by prostacyclin analogues was reduced in both 3- and 18-month old animals although endothelium (acetylcholine)-mediated relaxation was reduced in 18-month old DMO only. Endothelium-independent (sodium nitroprusside) relaxation was not affected. Pressure-induced myogenic tone, which controls local blood flow, was reduced in 18-month old CMO compared to 3-month old CMO. Interestingly, myogenic tone was maintained at a high level in 18-month old DMO even though agonist-induced vasoconstriction was not altered. These perturbations, in 18-months old DMO rats, were associated with an increased pMLC/MLC, pPKA/PKA ratio and an activated RhoA protein. Thus, we highlighted perturbations in the reactivity of resistance mesenteric arteries in DMO, at as early as 3 months of age, followed by the maintenance of high myogenic tone in older rats. These modifications are in favour of excessive vasoconstrictor tone. These results evidenced a fetal programming of vascular functions of resistance arteries in adult rats exposed in utero to maternal diabetes, which could explain a re-setting of vascular functions and, at least in part, the occurrence of hypertension later in life. 相似文献
74.
Joseph Khoory Jessica Estanislau Abdallah Elkhal Asmae Lazaar Mark I. Melhorn Abigail Brodsky Ben Illigens Itaru Hamachi Yasutaka Kurishita Alexander R. Ivanov Sergey Shevkoplyas Nathan I. Shapiro Ionita C. Ghiran 《PloS one》2016,11(1)
Acute, inflammatory conditions associated with dysregulated complement activation are characterized by significant increases in blood concentration of reactive oxygen species (ROS) and ATP. The mechanisms by which these molecules arise are not fully understood. In this study, using luminometric- and fluorescence-based methods, we show that ligation of glycophorin A (GPA) on human red blood cells (RBCs) results in a 2.1-fold, NADPH-oxidase-dependent increase in intracellular ROS that, in turn, trigger multiple downstream cascades leading to caspase-3 activation, ATP release, and increased band 3 phosphorylation. Functionally, using 2D microchannels to assess membrane deformability, GPS-ligated RBCs travel 33% slower than control RBCs, and lipid mobility was hindered by 10% using fluorescence recovery after photobleaching (FRAP). These outcomes were preventable by pretreating RBCs with cell-permeable ROS scavenger glutathione monoethyl ester (GSH-ME). Our results obtained in vitro using anti-GPA antibodies were validated using complement-altered RBCs isolated from control and septic patients. Our results suggest that during inflammatory conditions, circulating RBCs significantly contribute to capillary flow dysfunctions, and constitute an important but overlooked source of intravascular ROS and ATP, both critical mediators responsible for endothelial cell activation, microcirculation impairment, platelet activation, as well as long-term dysregulated adaptive and innate immune responses. 相似文献
75.
76.
77.
Mona Gazel Kadriye Çağlayan Hüseyin Başpınar Juan F. Mejia Samanta Paltrinieri Assunta Bertaccini Nicoletta Contaldo 《Journal of Phytopathology》2016,164(2):136-140
Symptoms resembling those associated with phytoplasma presence were observed in pomegranate (Punica granatum L.) trees in June 2012 in the Aegean Region of Turkey (Ayd?n province). The trees exhibiting yellowing, reduced vigour, deformations and reddening of the leaves and die‐back symptoms were analysed to verify phytoplasma presence. Total nucleic acids were extracted from fresh leaf midribs and phloem tissue from young branches of ten symptomatic and five asymptomatic plants. Nested polymerase chain reaction assays using universal phytoplasma‐specific 16S rRNA and tuf gene primers were performed. Amplicons were digested with Tru1I, Tsp509I and HhaI restriction enzymes, according to the primer pair employed. The phytoplasma profiles were identical to each other and to aster yellows (16SrI‐B) strain when digestion was carried out on 16Sr(I)F1/R1 amplicons. However, one of the samples showed mixed profiles indicating that 16SrI‐B and 16SrXII‐A phytoplasmas were present when M1/M2 amplicons were digested, the reamplification of this sample with tuf cocktail primers allowed to verify the presence of a 16SrXII‐A profile. One pomegranate aster yellows strain AY‐PG from 16S rRNA gene and the 16SrXII‐A amplicon from tuf gene designed strain STOL‐PG were directly sequenced and deposited in GenBank under the Accession Numbers KJ818293 and KP161063, respectively. To our knowledge, this is the first report of 16SrI‐B and 16SrXII‐A phytoplasmas in pomegranate trees. 相似文献
78.
Biocontrol of Fusarium Wilt and Growth Promotion of Tomato Plants Using Endophytic Bacteria Isolated from Solanum elaeagnifolium Stems
下载免费PDF全文
![点击此处可从《Journal of Phytopathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rania Aydi Ben Abdallah Hayfa Jabnoun‐Khiareddine Ahlem Nefzi Sonia Mokni‐Tlili Mejda Daami‐Remadi 《Journal of Phytopathology》2016,164(10):811-824
Seven culturable bacterial isolates, obtained from the internal stem tissues of Solanum elaeagnifolium and successfully colonizing the internal stem tissues of tomato cv. Rio Grande, were screened for their in vivo antifungal activity against Fusarium oxysporum f.sp. lycopersici (FOL) and their growth‐promoting potential on tomato plants. SV101 and SV104 isolates, assessed on pathogen‐challenged tomato plants led to a significant decrease (77–83%) in Fusarium wilt severity and vascular browning extent (76%), as compared to the inoculated and untreated control. Isolates enhanced growth parameters on pathogen‐challenged and unchallenged tomato plants. SV104 and SV101 isolates were most effective in suppressing disease and enhancing plant growth. These two isolates were identified as Bacillus sp. str. SV101 ( KU043040 ) and B. tequilensis str. SV104 ( KU976970 ). They displayed antifungal activity against FOL; pathogen growth was inhibited by 64% and an inhibition zone (11.50 and 19.75 mm) against FOL could be formed using whole cell suspensions. SV101 and SV104 extracellular metabolites also inhibited FOL growth by 20 and 55%, respectively, as compared to control. B. tequilensis str. SV104 was shown to produce protease, chitinase, pectinase, IAA and siderophores. Bacillus sp. str. SV101 displayed pectinase activity and was found to be an IAA‐producing and phosphate‐solubilizing agent. To our knowledge, this is the first study reporting on S. elaeagnifolium use as a potential source of potent biocontrol and plant growth‐promoting agents. 相似文献
79.
Wheat and barley are two of the founder crops of the agricultural revolution that took place 10,000 years ago in the Fertile Crescent and both crops remain among the world's most important crops. Domestication of these crops from their wild ancestors required the evolution of traits useful to humans, rather than survival in their natural environment. Of these traits, grain retention and threshability, yield improvement, changes to photoperiod sensitivity and nutritional value are most pronounced between wild and domesticated forms. Knowledge about the geographical origins of these crops and the genes responsible for domestication traits largely pre-dates the era of nextgeneration sequencing, although sequencing will lead to new insights. Molecular markers were initially used to calculate distance(relatedness), genetic diversity and to generate genetic maps which were useful in cloning major domestication genes. Both crops are characterized by large,complex genomes which were long thought to be beyond the scope of whole-genome sequencing. However, advances in sequencing technologies have improved the state of genomic resources for both wheat and barley. The availability of reference genomes for wheat and some of its progenitors,as well as for barley, sets the stage for answering unresolved questions in domestication genomics of wheat and barley. 相似文献
80.
Mohamed A. Dkhil Mona F. Khalil Marwa S.M. Diab Amira A. Bauomy Simeon Santourlidis Esam M. Al-Shaebi Saleh Al-Quraishy 《Saudi Journal of Biological Sciences》2019,26(7):1468-1472
Nanomedicine is one of the most important methods used to treat human diseases including parasitic diseases. Schistosomiasis is a major parasitic disease that affects human health in tropical regions. Whilst Praziquantel is the main classic antischistosomal drug, new drugs are required due to the poor effect of the drug on the parasite juveniles and immature worms, and the emergence of drug resistant strains of Schistosoma. The present study aimed to examine the curative roles of both gold and selenium nanoparticles on jejunal tissues of mice infected with Schistosoma mansoni. Transmission electron microscopy was used for characterization of nanoparticles. Gold nanoparticles of 1 mg/kg mice body weight and selenium nanoparticles 0.5 mg/kg body weight were inoculated separately into mice infected with S. mansoni. The parasite induced a significant decrease in glutathione levels; however, the levels of nitric oxide and malondialdehyde were significantly increased. Additionally, the parasite introduced deteriorations in histological architecture of the jejunal tissue. Treatment of mice with metal nanoparticles reduced the levels of body weight changes, oxidative stress and histological impairment in the jejunal tissue significantly. Therefore, our results revealed the protective role of both selenium and gold nanoparticles against jejunal injury in mice infected with S. mansoni. 相似文献