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241.
Aim
Many aspects of vegetation response to increased drought remain uncertain but it is expected that phenotypic plasticity may be key to early adaptation of plants to environmental stress. In this work we observe the response of specific leaf area (SLA) of woody shrub vegetation to the summer drought typical of the Mediterranean climate. In addition, to observe the possible interaction between the impact of drought and the environmental characteristics of the ecosystems, communities from different edaphic and structural contexts distributed along the double stress gradient of the Mediterranean mountains (high temperature and low precipitation at low elevation; low temperature and high irradiation at high elevation) have been analysed.Location
Central Mountain range of the Iberian Peninsula.Methods
Along the entire altitudinal gradient, 33 shrub communities belonging to different habitat typologies (shrublands, rocky areas, hedgerows, understorey) were sampled before and after the passage of summer, both in 2017 and 2019. A total of 1724 individuals and 15,516 leaves were collected and measured to estimate the mean values and diversity of SLA of each community.Results
The community-weighted mean and functional divergence have inverse quadratic relationships with the environmental gradient. Shrub communities at both ends of the gradient have low mean SLA values and high functional divergence of this trait. Summer drought implies a generalised decrease in the mean SLA of the communities throughout the gradient, as well as an alteration in functional richness and uniformity. However, the effect of summer drought on the plant community is mediated by the microenvironmental characteristics of its habitat.Conclusions
Drought acclimatisation of shrub communities through phenotypic plasticity leads to rapid changes in their functional leaf structure. In the long term, our results point to an increase in plant conservative strategies, reduced ecosystem productivity, slower nutrient recycling and the reduction of communities of specific habitats as drought increases. 相似文献242.
243.
Izabela Gutowska Irena Baranowska-Bosiacka Marta Rybicka Iwona Noceń Wioletta Dudzińska Mariola Marchlewicz Barbara Wiszniewska Dariusz Chlubek 《Biological trace element research》2011,139(3):332-340
The mineral content of tooth hard tissue may influence the rate of decay change. Considering this fact, we aimed at examining
if type 1 diabetes might be a contributing factor to the appearance of tooth decay. The experiment was conducted on female
Wistar rats. To induce diabetes, rats were intravenously injected with 1 mL streptozocine 0.01 M citrate buffer. The control
group of rats was injected with 1 mL 0.01 M citrate buffer only. After 10 days, teeth and blood serum samples were obtained.
Fluoride concentration was determined by potentiometer method, and calcium and magnesium, by AAS. Serum concentrations of
glucose and estradiol in the diabetic rats were significantly higher compared to the control group. In the experimental group,
a statistically significant decrease of fluorine concentration in both teeth and serum were observed. Calcium and magnesium
concentrations in blood serum and dental magnesium concentration were significantly higher in rats with type 1 diabetes compared
with the control. A downward trend in the content of dental calcium in streptozotocin-induced diabetic rats was observed.
The results obtained indicate that caries initiation and progression could be promoted by metabolic changes associated with
diabetes affecting the mineral composition of tooth hard tissue. 相似文献
244.
Maria Jose Perez-Calatayud Antonio Vicente Menendez Francisco Javier Celada-Alvarez Antonio Jose Conde-Moreno Mariola Bernisz Franoise Lliso Vicente Carmona Jose Gimeno-Olmos Carlos Botella Jose Perez-Calatayud 《Reports of Practical Oncology and Radiotherapy》2021,26(1):119
BackgroundUtilization of stereotactic radiosurgery (SRS) for brain metastases (BM) has become the technique of choice as opposed to whole brain radiation therapy (WBRT). The aim of this work is to evaluate the feasibility and potential benefits in terms of normal tissue (NT) and dose escalation of volumetric modulated arc therapy (VMAT) in SRS metastasis treatment. A VMAT optimization procedure has therefore been developed for internal dose scaling which minimizes planner dependence.Materials and methodsFive patient-plans incorporating treatment with frame-based SRS with dynamic conformal arc technique (DA) were re-planned for VMAT. The lesions selected were between 4–6 cm3. The same geometry used in the DA plans was maintained for the VMAT cases. A VMAT planning procedure was performed attempting to scale the dose in inner auxiliary volumes, and to explore the potential for dose scaling with this technique. Comparison of dose-volume histogram (DVH) parameters were obtained.ResultsVMAT allows a superior NT sparing plus conformity and dose scaling using the auxiliary volumes. The VMAT results were significantly superior in NT sparing, improving both the V10 and V12 values in all cases, with a 2–3 cm3 saving. In addition, VMAT improves the dose coverage D95 by about 0.5 Gy. The objective of dose escalation was achieved with VMAT with an increment of the Dmean and the Dmedian of about 2 Gy.ConclusionsThis work shows a benefit of VMAT in SRS treatment with significant NT sparing. A VMAT optimization procedure, based on auxiliary inner volumes, has been developed, enabling internal dose escalation. 相似文献
245.
Tomasz Jagielski Henryk Krukowski Mariola Bochniarz Tomasz Piech Katarzyna Roeske Zofia Bakuła Łukasz Wlazło Piotr Woch 《Microbial biotechnology》2019,12(3):556-566
The Prototheca algae have recently emerged as an important cause of bovine mastitis globally. Here, we present results of a first large-scale, cross-country survey on the prevalence of Prototheca spp. in dairy cows, and their environment in Poland. A total of 1211 samples were collected and microbiologically analysed. Included within this number were milk (n = 638), body swabs (n = 374) and environmental samples (n = 199), originating from 400 dairy cows and their surroundings, on 16 dairy farms, based in all major provinces of the country. Prototheca spp. were the third, after Streptococcus and Staphylococcus spp., most common mastitis pathogens. The overall prevalence of protothecal mastitis was 8.3% (33/400), with the majority (75.8%) of cases having a subclinical course, and all but one attributable to P. zopfii genotype 2. Prototheca spp. were cultured from body swabs of both healthy and mastitic cows, yet the isolation rate among the latter was conspicuously lower (12.3% vs. 17.8%). Forty-two (21.2%) environmental samples yielded growth of Prototheca spp. However, no clear association between Prototheca mastitis in dairy cows and the algal isolation from the herd environment was found. Nor was there any association between the environmental recovery of the algae and farm management practices. 相似文献
246.
247.