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1.
This systematic review and meta-analysis aimed to investigate the associations between weather conditions and physical activity (PA) and sedentary time (ST) in children and adolescents. A systematic search of six databases identified 11,816 articles, of which 26 studies were included in the review. Several weather conditions were included, such as rainfall, temperature, wind speed, day length, sunlight, humidity, snowfall, and clouds. Meta-analyses showed that higher temperatures were associated with more moderate-to-vigorous PA, while lower temperature and heavily rainfall was associated with longer ST. Children and adolescents showed more PA and less ST during favorable weather conditions. Future longitudinal and intervention studies on PA and ST should focus on how weather conditions promote or hinder these behaviors.  相似文献   
2.
Of the three types of toxicity known so far in Portuguese shellfish, only diarrhetic shellfish poisoning (DSP) and amnesic shellfish poisoning (ASP) are produced by microalgae that seem to have been present in the last decades or centuries. The most important paralytic shellfish poisoning (PSP) producer, Gymnodinium catenatum, is hypothesised to have been introduced quite recently as only in 1976 PSP toxicity was detected for the first time in shellfish from Galicia, NW Iberian Peninsula. While ASP presents very short episodes of contamination, the concentration of DSP toxins in some years surpasses human safety values for much longer periods. It is traditionally stated that shellfish should be consumed in 'months with R' (September-April). A retrospective study of the maximum monthly DSP levels attained in mussels from a coastal lagoon-Ria de Aveiro-between 1994 and 2001, showed that the highest frequency of months with concentrations surpassing the safety level of 2 microg/g digestive glands were found in June-September, followed by May and October. These months correspond with the months of lowest historical average rainfall in the period 1941-1998.Oscillations in the rainfall pattern coincided with earliest (or latest) detection by HPLC of DSP toxins in mussel in the years studied. In a semi-closed lagunar environment prone to in situ growth of DSP-producer microalgae, like Dinophysis acuminata, rainfall affects river output, lowering salinity and disrupting water column stability that favours Dinophysis growth. The seasonality of DSP recurrence may be connected to the folk adage on safety of shellfish consumption, after many years of empirical observations by coastal populations of diarrhoea episodes in summertime.  相似文献   
3.
We investigated the periodicity of Plasmodium vivax and P. falciparum incidence in time-series of malaria data (1990–2010) from three endemic regions in Venezuela. In particular, we determined whether disease epidemics were related to local climate variability and regional climate anomalies such as the El Niño Southern Oscillation (ENSO). Malaria periodicity was found to exhibit unique features in each studied region. Significant multi-annual cycles of 2- to about 6-year periods were identified. The inter-annual variability of malaria cases was coherent with that of SSTs (ENSO), mainly at temporal scales within the 3–6 year periods. Additionally, malaria cases were intensified approximately 1 year after an El Niño event, a pattern that highlights the role of climate inter-annual variability in the epidemic patterns. Rainfall mediated the effect of ENSO on malaria locally. Particularly, rains from the last phase of the season had a critical role in the temporal dynamics of Plasmodium. The malaria–climate relationship was complex and transient, varying in strength with the region and species. By identifying temporal cycles of malaria we have made a first step in predicting high-risk years in Venezuela. Our findings emphasize the importance of analyzing high-resolution spatial–temporal data to better understand malaria transmission dynamics.  相似文献   
4.
The population dynamics of the larval and adult life stages of the malaria vector Anopheles gambiae Giles were studied in Miwani, western Kenya, in relation to meteorological conditions. Larval density within a habitat, the number of larval habitats and sibling species composition were investigated as determinants of larval population dynamics. Female vector densities inside local houses and sibling species composition were investigated as determinants of adult population dynamics. Larval densities were estimated using a modified area-sampling method. Within the habitats, all instars showed a highly aggregated distribution, with the exception of second instars. A longitudinal study on the larval populations of A. gambiae s.l. in two different types of habitat (dirt track and ditch) was carried out, using a novel sampling procedure. A. gambiae s.s. and Anopheles arabiensis, the two sibling species occurring sympatrically in the study area, showed some spatial segregation between the two types of habitat. Rainfall was significantly correlated with the number of A. gambiae s.l. larval habitats during the first 6 weeks of study taking 1 week time lag into account, while over the entire 5-month study period correlations were less clear. With 1 week time lag, rainfall was also significantly correlated with the number of female A. gambiae s.l. collected from CDC-light traps in the study houses. Both larval and adult populations showed a significant increase in the proportion of A. gambiae s.s. within the mixed population of A. gambiae s.s. and A. arabiensis over time. Although not significantly correlated, the ratio of rainfall over precipitation/potential evapotranspiration (P/PE), indicative of the humidity conditions in the area, was probably the driving force of this increase.  相似文献   
5.
In the present study, factors that influence the distribution and variation of 7Be in Hsinchu, Taiwan were elucidated. The 7Be activity including the deposition flux and air concentration was continuously monitored and recorded throughout a 15-year period (1996-2010). To explain the observed variability in the 7Be activity over time, air concentration and deposition flux of 7Be were correlated to rainfall and solar activity. The monthly average deposition flux and air concentration of 7Be were inversely related to solar activity with the 11-year cycle and were not strongly correlated to rainfall. The highest seasonal deposition flux of 7Be occurred in March, which is commonly referred to as the spring maximum, due to air-mass mixing processes in the troposphere. The air concentration of 7Be was seasonally variable and was significantly affected by monsoons. The lowest deposition flux and air concentration of 7Be were observed in July and August due to the occurrence of southwest monsoons from low latitudes, which carry air masses with low concentrations of 7Be. The deposition flux was enhanced by precipitation, which increased the deposition velocity, transferring more 7Be from the troposphere to the ground. The fraction of dry to total deposition varied seasonally and was equal to 9.86%, on average.  相似文献   
6.

Objective

To evaluate the relationship between meteorological factors in North-western Greece and the incidence of bronchiolitis.

Methods

Meteorological data (air temperature and rainfall) for Ioannina city in North-western Greece and medical data from hospitalised patients at University Hospital of Ioannina were collected between January 2002 and December 2013. The association between meteorological factors and rate of hospitalisation due to bronchiolitis was investigated. The data processing was done using the Pearson product-moment correlation coefficient and applying the chi-square test at contingency tables of the parameters.

Results

Of the 792 hospitalised cases, 670 related to infants (<1 year) and 122 concerned patients aged 1–2 years old. The disease is more common among boys (59.5%) than girls (40.5%). The disease course through the year has a double variation with a main maximum in March and a main minimum in August. The statistical study showed statistically significant correlation of bronchiolitis with: (a) the temperature parameters on an annual basis; (b) precipitation in autumn and dryness in spring; and (c) with sudden changes in diurnal temperature range on an annual basis.

Conclusion

A peak incidence of bronchiolitis was noticed in cold and wet seasons during the five days preceding hospitalisation.  相似文献   
7.
Behavioral ecologists are increasingly adopting sophisticated non-invasive methods for measuring glucocorticoids from “excreta” because samples are easy to collect, animals are left undisturbed, and measures may be more reflective of external events than serum samples. Some of the most common predictors for hormone profiles in wild animals are seasonal changes in ecology and behavior. For example, we might expect baseline glucocorticoid levels to track changes in food availability or other seasonal stressors such as unusually high or low temperatures. Geladas (Theropithecus gelada) are one of the few non-human primates that live at extremely high altitudes where nighttime temperatures often dip below freezing. However, the physiological effects of this relatively inhospitable environment have never been examined in this species. Here we validate a “field-friendly” method of hormone extraction from gelada feces and demonstrate that this method can be used to detect seasonal and altitudinal differences in glucocorticoid metabolites for this species. We use two years of climatological and hormonal data from a wild population of geladas to test the hypothesis that geladas exhibit elevated glucocorticoids under environmentally “challenging” conditions — mainly, when temperatures and rainfall are low and altitude is high. Our results indicate that cold temperatures and high altitude predicted elevated glucocorticoids, but low rainfall did not. Therefore, we suggest a metabolic hypothesis (as opposed to a nutritional hypothesis) to explain this result. However, at the present time, we cannot rule out a behavioral stress hypothesis.  相似文献   
8.
「目的」探索用气温和降雨量预报急性血吸虫病检出率的新途径。「方法」收集我国湖北省四湖地区1976~1989年急性血吸虫人出率(急血率)和相应地区7月气温和降雨量资料,并用SPSS8.0软件做多元回归分析。「结果」该区1976~1989年年急血率(y)与7月份平均气温(x2)呈负相关(r=-0.7495,P〈0.05),与7月份平均降雨量(x1)呈正相关(r=0.7357,P〈0.05)。所获预报模  相似文献   
9.
目的探讨降雨对环境地表γ空气比释动能率测量的影响规律,以便修正降雨时环境地表γ空气比释动能率测量结果。方法 分析降雨对环境地表γ空气比释动能率测量的影响因素,从理论上建立相关因素的微分方程,并解方程得到降雨对环境地表γ空气比释动能率测量影响规律的数学模型。通过几个实例来分析探讨这一规律。结果 降雨对环境地表γ空气比释动能率测量影响规律的数学模型与实测数据曲线的趋势相吻合。结论 使用本研究建立的降雨对环境地表γ空气比释动能率测量影响规律的理论公式,可有效地修正降雨对环境地表γ空气比释动能率测量影响。  相似文献   
10.
本文在分析粤北自然条件和农业生产主要特点基础上,运用光能利用测算原理,热潜势测定方法,侧算分析了八种主要作物及其相应熟制的生产潜势,剖析了水肥转化效率。潜势分析表明:水稻和甘蔗(主要在本区南部)光能利用率高,热潜势利用率大,是当地的优势作物;花生、番薯、大豆光热潜势利用偏低,有待提高;油菜、小麦尚待克服当地限制因素,潜势始能发挥。双季稻一年二熟或与油菜、小麦组成的一年三熟是当地当前的高产熟制。并就充分利用粤北光热水肥资源提出了建议。  相似文献   
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