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101.
Genevieve LaCon Amy C. Morrison Helvio Astete Steven T. Stoddard Valerie A. Paz-Soldan John P. Elder Eric S. Halsey Thomas W. Scott Uriel Kitron Gonzalo M. Vazquez-Prokopec 《PLoS neglected tropical diseases》2014,8(8)
Background
Empiric evidence shows that Aedes aegypti abundance is spatially heterogeneous and that some areas and larval habitats produce more mosquitoes than others. There is a knowledge gap, however, with regards to the temporal persistence of such Ae. aegypti abundance hotspots. In this study, we used a longitudinal entomologic dataset from the city of Iquitos, Peru, to (1) quantify the spatial clustering patterns of adult Ae. aegypti and pupae counts per house, (2) determine overlap between clusters, (3) quantify the temporal stability of clusters over nine entomologic surveys spaced four months apart, and (4) quantify the extent of clustering at the household and neighborhood levels.Methodologies/Principal Findings
Data from 13,662 household entomological visits performed in two Iquitos neighborhoods differing in Ae. aegypti abundance and dengue virus transmission was analyzed using global and local spatial statistics. The location and extent of Ae. aegypti pupae and adult hotspots (i.e., small groups of houses with significantly [p<0.05] high mosquito abundance) were calculated for each of the 9 entomologic surveys. The extent of clustering was used to quantify the probability of finding spatially correlated populations. Our analyses indicate that Ae. aegypti distribution was highly focal (most clusters do not extend beyond 30 meters) and that hotspots of high vector abundance were common on every survey date, but they were temporally unstable over the period of study.Conclusions/Significance
Our findings have implications for understanding Ae. aegypti distribution and for the design of surveillance and control activities relying on household-level data. In settings like Iquitos, where there is a relatively low percentage of Ae. aegypti in permanent water-holding containers, identifying and targeting key premises will be significantly challenged by shifting hotspots of Ae. aegypti infestation. Focusing efforts in large geographic areas with historically high levels of transmission may be more effective than targeting Ae. aegypti hotspots. 相似文献102.
Trahtemberg U Atallah M Krispin A Verbovetski I Mevorach D 《Apoptosis : an international journal on programmed cell death》2007,12(10):1769-1780
One hallmark of programmed cell death (PCD) is redistribution of phosphatidylserine (PS) to the plasma membrane’s outer leaflet.
Annexin V is widely used in cell death research due to its calcium-dependent ability to bind phosphatidylserine, thus marking
apoptotic cells. However, calcium is invariably used at high concentrations in annexin V staining, at doses that can induce
cell death. We used flow cytometric annexin V staining, together with propidium iodide and TMRM for determination of dissipation
of mitochondrial potential, with a variety of calcium concentrations, cell media, and incubation times, to identify a possible
bias in PCD determination of human primary leukocytes. Here we show that measurements of PCD in human monocytes, polymorphonuclear
cells, and monocyte-derived dendritic cells using annexin V may be dramatically affected by calcium concentration, time of
incubation on ice, and media choice. We propose a method that enables accurate and unbiased annexin V staining, without affecting
results.
Uriel Trahtemberg and Mizhir Atallah contributed equally to this publication. 相似文献
103.
Sarah Anne Guagliardo Amy C. Morrison Jose Luis Barboza Edwin Requena Helvio Astete Gonzalo Vazquez-Prokopec Uriel Kitron 《PLoS neglected tropical diseases》2015,9(4)
Background and Objectives
The dramatic range expansion of the dengue vector Aedes aegypti is associated with various anthropogenic transport activities, but little is known about the underlying mechanisms driving this geographic expansion. We longitudinally characterized infestation of different vehicle types (cars, boats, etc.) to estimate the frequency and intensity of mosquito introductions into novel locations (propagule pressure).Methods
Exhaustive adult and immature Ae. aegypti collections were performed on six different vehicle types at five ports and two bus/ taxi departure points in the Amazonian city of Iquitos, Peru during 2013. Aquatic vehicles included 32 large and 33 medium-sized barges, 53 water taxis, and 41 speed boats. Terrestrial vehicles sampled included 40 buses and 30 taxis traveling on the only highway in the region. Ae. aegypti adult infestation rates and immature indices were analyzed by vehicle type, location within vehicles, and sampling date.Results
Large barges (71.9% infested) and medium barges (39.4% infested) accounted for most of the infestations. Notably, buses had an overall infestation rate of 12.5%. On large barges, the greatest number of Ae. aegypti adults were found in October, whereas most immatures were found in February followed by October. The vast majority of larvae (85.9%) and pupae (76.7%) collected in large barges were produced in puddles formed in cargo holds.Conclusions
Because larges barges provide suitable mosquito habitats (due to dark, damp cargo storage spaces and ample oviposition sites), we conclude that they likely serve as significant contributors to mosquitoes’ propagule pressure across long distances throughout the Peruvian Amazon. This information can help anticipate vector population mixing and future range expansions of dengue and other viruses transmitted by Ae. aegypti. 相似文献104.
Avian host community structure and prevalence of West Nile virus in Chicago,Illinois 总被引:1,自引:0,他引:1
Scott R. Loss Gabriel L. Hamer Edward D. Walker Marilyn O. Ruiz Tony L. Goldberg Uriel D. Kitron Jeffrey D. Brawn 《Oecologia》2009,159(2):415-424
Vertebrate host diversity has been postulated to mediate prevalence of zoonotic, vector-borne diseases, such that as diversity
increases, transmission dampens. This “dilution effect” is thought to be caused by distribution of infective bites to incompetent
reservoir hosts. We quantified avian species richness, avian seroprevalence for antibodies to West Nile virus (WNV), and infection
of WNV in Culex mosquitoes, in the Chicago metropolitan area, Illinois, USA, a region of historically high WNV activity. Results indicated
high overall avian seroprevalence and variation in seroprevalence across host species; however, there was no negative correlation
between avian richness and Culex infection rate or between richness and infection status in individual birds. Bird species with high seroprevalence, especially
northern cardinals and mourning doves, may be important sentinels for WNV in Chicago, since they were common and widespread
among all study sites. Overall, our results suggest no net effect of increasing species richness to West Nile virus transmission
in Chicago. Other intrinsic and extrinsic factors, such as variation in mosquito host preference, reservoir host competence,
temperature, and precipitation, may be more important than host diversity for driving interannual variation in WNV transmission.
These results from a fine-scale study call into question the generality of a dilution effect for WNV at coarser spatial scales. 相似文献
105.
Luis F. Chaves Amy C. Morrison Uriel D. Kitron Thomas W. Scott 《Global Change Biology》2012,18(2):457-468
Aedes aegypti is one of the most common urban tropical mosquito species and an important vector of dengue, chikungunya, and yellow fever viruses. It is also an organism with a complex life history where larval stages are aquatic and adults are terrestrial. This ontogenetic niche shift could shape the density‐dependent regulation of this and other mosquito species, because events that occur during the larval stages impact adult densities. Herein, we present results from simple density‐dependent mathematical models fitted using maximum likelihood methods to weekly time series data from Puerto Rico and Thailand. Density‐dependent regulation was strong in both populations. Analysis of climatic forcing indicated that populations were more sensitive to climatic variables with low kurtosis, i.e., climatic factors highly variable around the median, rainfall in Puerto Rico, and temperature in Thailand. Changes in environmental variability appear to drive sharp changes in the abundance of mosquitoes. The identification of density‐independent (i.e., exogenous) variables forcing sharp changes in disease vector populations using the exogenous factors statistical properties, such as kurtosis, could be useful to assess the impacts of changing climate patterns on the transmission of vector‐borne diseases. 相似文献
106.
107.
Xiaoxia Wang David Gurarie Peter L. Mungai Eric M. Muchiri Uriel Kitron Charles H. King 《PLoS neglected tropical diseases》2012,6(11)
Background
Schistosomiasis remains a significant health burden in many areas of the world. Morbidity control, focused on limiting infection intensity through periodic delivery of anti-schistosomal medicines, is the thrust of current World Health Organization guidelines (2006) for reduction of Schistosoma-related disease. A new appreciation of the lifetime impact of repeated Schistosoma infection has directed attention toward strategies for greater suppression of parasite infection per se, with the goal of transmission interruption. Variations in drug schedules involving increased population coverage and/or treatment frequency are now undergoing field trials. However, their relative effectiveness in long-term infection suppression is presently unknown.Methodology/Principal Findings
Our study used available field data to calibrate advanced network models of village-level Schistosoma transmission to project outcomes of six different community- or school age-based programs, as compared to the impact of current 2006 W.H.O. recommended control strategies. We then scored the number of years each of 10 typical villages would remain below 10% infection prevalence (a practicable level associated with minimal prevalence of disease). All strategies that included four annual treatments effectively reduced community prevalence to less than 10%, while programs having yearly gaps (‘holidays’) failed to reach this objective in half of the communities. Effective post-program suppression of infection prevalence persisted in half of the 10 villages for 7–10 years, whereas in five high-risk villages, program effects on prevalence lasted zero to four years only.Conclusions/Significance
At typical levels of treatment adherence (60 to 70%), current WHO recommendations will likely not achieve effective suppression of Schistosoma prevalence unless implemented for ≥6 years. Following more aggressive 4 year annual intervention, some communities may be able to continue without further intervention for 8–10 years, while in higher-risk communities, annual treatment may prove necessary until eco-social factors fostering transmission are removed. Effective ongoing surveillance and locally targeted annual intervention must then become their mainstays of control. 相似文献108.
Wilson AJ Gelin U Perron MC Réale D 《Proceedings. Biological sciences / The Royal Society》2009,276(1656):533-541
Aggressive behaviours are necessarily expressed in a social context, such that individuals may be influenced by the phenotypes, and potentially the genotypes, of their social partners. Consequently, it has been hypothesized that indirect genetic effects (IGEs) arising from the social environment will provide a major source of heritable variation on which selection can act. However, there has been little empirical scrutiny of this to date. Here we test this hypothesis in an experimental population of deer mice (Peromyscus maniculatus). Using quantitative genetic models of five aggression traits, we find repeatable and heritable differences in agonistic behaviours of focal individuals when presented with an opponent mouse. For three of the traits, there is also support for the presence of IGEs, and estimated correlations between direct and indirect genetic (rAO,F) effects were high. As a consequence, any selection for aggression in the focal individuals should cause evolution of the social environment as a correlated response. In two traits, strong positive rAO,F will cause the rapid evolution of aggression, while in a third case changes in the phenotypic mean will be constrained by negative covariance between direct and IGEs. Our results illustrate how classical analyses may miss important components of heritable variation, and show that a full understanding of evolutionary dynamics requires explicit consideration of the genetic component of the social environment. 相似文献
109.
Adi Tabib Alon Krispin Uriel Trahtemberg Inna Verbovetski Mario Lebendiker Tsafi Danieli Dror Mevorach 《PloS one》2009,4(8)
In our previous study, we have found that thrombospondin-1 (TSP-1) is synthesized de novo upon monocyte and neutrophil apoptosis, leading to a phagocytic and tolerizing phenotype of dendritic cells (DC), even prior to DC-apoptotic cell interaction. Interestingly, we were able to show that heparin binding domain (HBD), the N-terminal portion of TSP-1, was cleaved and secreted simultaneously in a caspase- and serine protease- dependent manner. In the current study we were interested to examine the role of HBD in the clearance of apoptotic cells, and whether the phagocytic and tolerizing state of DCs is mediated by the HBD itself, or whether the entire TSP-1 is needed. Therefore, we have cloned the human HBD, and compared its interactions with DC to those with TSP-1. Here we show that rHBD by itself is not directly responsible for immune paralysis and tolerizing phenotype of DCs, at least in the monomeric form, but has a significant role in rendering DCs phagocytic. Binding of TSP-1-C-terminal domain on the other hand induces a tolerizing phenotype in dendritic cells. 相似文献
110.
Gonzalo M. Vazquez-Prokopec Cynthia Spillmann Mario Zaidenberg Uriel Kitron Ricardo E. Gürtler 《PLoS neglected tropical diseases》2009,3(1)