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141.
Local knowledge systems are not considered in the conservation of fragile seagrass marine ecosystems. In fact, little is known about the utility of seagrasses in local coastal communities. This is intriguing given that some local communities rely on seagrasses to sustain their livelihoods and have relocated their villages to areas with a rich diversity and abundance of seagrasses. The purpose of this study is to assist in conservation efforts regarding seagrasses through identifying Traditional Ecological Knowledge (TEK) from local knowledge systems of seagrasses from 40 coastal communities along the eastern coast of India. We explore the assemblage of scientific and local traditional knowledge concerning the 1. classification of seagrasses (comparing scientific and traditional classification systems), 2. utility of seagrasses, 3. Traditional Ecological Knowledge (TEK) of seagrasses, and 4. current conservation efforts for seagrass ecosystems. Our results indicate that local knowledge systems consist of a complex classification of seagrass diversity that considers the role of seagrasses in the marine ecosystem. This fine-scaled ethno-classification gives rise to five times the number of taxa (10 species = 50 local ethnotaxa), each with a unique role in the ecosystem and utility within coastal communities, including the use of seagrasses for medicine (e.g., treatment of heart conditions, seasickness, etc.), food (nutritious seeds), fertilizer (nutrient rich biomass) and livestock feed (goats and sheep). Local communities are concerned about the loss of seagrass diversity and have considerable local knowledge that is valuable for conservation and restoration plans. This study serves as a case study example of the depth and breadth of local knowledge systems for a particular ecosystem that is in peril.  相似文献   
142.
1. Arbuscular mycorrhizal fungi (AMF) commonly colonise isoetid species inhabiting oxygenated sediments in oligotrophic lakes but are usually absent in other submerged plants. We hypothesised that organic enrichment of oligotrophic lake sediments reduces AMF colonisation and hyphal growth because of sediment O2 depletion and low carbon supply from stressed host plants. 2. We added organic matter to sediments inhabited by isoetids and measured pore‐water chemistry (dissolved O2, inorganic carbon, Fe2+ and ), colonisation intensity of roots and hyphal density after 135 days of exposure. 3. Addition of organic matter reduced AMF colonisation of roots of both Lobelia dortmanna and Littorella uniflora, and high additions stressed the plants. Even small additions of organic matter almost stopped AMF colonisation of initially un‐colonised L. uniflora, though without reducing plant growth. Mean hyphal density in sediments was high (6 and 15 m cm?3) and comparable with that in terrestrial soils (2–40 m cm?3). Hyphal density was low in the upper 1 cm of isoetid sediments, high in the main root zone between 1 and 8 cm and positively related to root density. Hyphal surface area exceeded root surface area by 1.7–3.2 times. 4. We conclude that AMF efficiently colonise isoetids in oligotrophic sediments and form extensive hyphal networks. Small additions of organic matter to sediments induce sediment anoxia and reduce AMF colonisation of roots but cause no apparent plant stress. High organic addition induces night‐time anoxia in both the sediment and the plant tissue. Tissue anoxia reduces root growth and AMF colonisation, probably because of restricted translocation of nutrient ions and organic solutes between roots and leaves. Isoetids should rely on AMF for P uptake on nutrient‐poor mineral sediments but are capable of growing without AMF on organic sediments.  相似文献   
143.
Two studies were conducted to determine the effect of habitat selection and trap placement on catches of Scolytidae and Cerambycidae (Coleoptera) in northeastern U.S. forests. In a nonreplicated case study, four habitat types--closed canopy hardwood stand, closed canopy conifer stand, a low-intensity thinned Pinus strobus L. stand, and a high-intensity thinned P. strobus stand--were surveyed using alpha-pinene, ethanol, ipsenol, ipsdienol, and lanierone. Average trap catches, species richness, and the number of unique species captured were all highest in at least one of the thinned habitats. A second experiment that was replicated evaluated the placement of traps in relation to habitat patches. Semiochemical-baited traps (alpha-pinene and ethanol) were placed under a closed canopy forest, along an edge, and in a clearing and tested for effects on Scolytidae and Cerambycidae trap catches. Abundance and species richness were generally higher in the closed canopy and edge placements compared with traps in the open area. The highest number of unique species were captured in the edge and clearing.  相似文献   
144.
Trophic state, eutrophication and nutrient criteria in streams   总被引:2,自引:0,他引:2  
Trophic state is the property of energy availability to the food web and defines the foundation of community integrity and ecosystem function. Describing trophic state in streams requires a stoichiometric (nutrient ratio) approach because carbon input rates are linked to nitrogen and phosphorus supply rates. Light determines the source of carbon. Cross system analyses, small experiments and ecosystem level manipulations have recently advanced knowledge about these linkages, but not to the point of building complex predictive models that predict all effects of nutrient pollution. Species diversity could indicate the natural distribution of stream trophic status over evolutionary time scales. Delineation of factors that control trophic state and relationships with biological community properties allows determination of goals for management of stream biotic integrity.  相似文献   
145.
The generation of plant disease resistance gene specificities   总被引:12,自引:0,他引:12  
We are gaining an understanding of the molecular basis of resistance specificity and of the natural processes that generate different specificities. This is a prerequisite for the genetic engineering of new plant disease-resistance genes to control diseases for which naturally occurring resistance is inadequate. DNA sequence analysis indicates that point mutation, recombination and selection can generate and maintain the high levels of polymorphism observed in resistance genes. Comparisons of closely related resistance proteins indicate that specificity can be determined by variation in at least two regions. One of these contains leucine-rich repeats, which are a common feature of most resistance proteins.  相似文献   
146.
Recently, increased attention has been directed towards medicinal extracts as potential new drug candidates for dementia. Ginger has long been used as an important ingredient in cooking and traditional herbal medicine. In particular, ginger has been known to have disease-modifying effects in Alzheimer's disease (AD). However, there is no evidence of which constituents of ginger exhibit therapeutic effects against AD. A growing number of experimental studies suggest that 6-shogaol, a bioactive component of ginger, may play an important role as a memory-enhancing and anti-oxidant agent against neurological diseases. 6-Shogaol has also recently been shown to have anti-neuroinflammatory effects in lipopolysaccharide (LPS)-treated astrocytes and animal models of Parkinson’s disease, LPS-induced inflammation and transient global ischemia. However, it is still unknown whether 6-shogaol has anti-inflammatory effects against oligomeric forms of the Aβ (AβO) in animal brains. Furthermore, the effects of 6-shogaol against memory impairment in dementia models are also yet to be investigated. In this study, we found that administration of 6-shogaol significantly reduced microgliosis and astrogliosis in intrahippocampal AβO-injected mice, ameliorated AβO and scopolamine-induced memory impairment, and elevated NGF levels and pre- and post-synaptic marker in the hippocampus. All these results suggest that 6-shogaol may play a role in inhibiting glial cell activation and reducing memory impairment in animal models of dementia.  相似文献   
147.

Background:

There is growing evidence that seasonal influenza vaccination in pregnancy has benefits for mother and baby. We determined influenza vaccination rates among pregnant women during the 2 nonpandemic influenza seasons following the 2009 H1N1 pandemic, explored maternal factors as predictors of influenza vaccination status and evaluated the association between maternal influenza vaccination and neonatal outcomes.

Methods:

We used a population-based perinatal database in the province of Nova Scotia, Canada, to examine maternal vaccination rates, determinants of vaccination status and neonatal outcomes. Our cohort included women who gave birth between Nov. 1, 2010, and Mar. 31, 2012. We compared neonatal outcomes between vaccinated and unvaccinated women using logistic regression analysis.

Results:

Overall, 1958 (16.0%) of 12 223 women in our cohort received the influenza vaccine during their pregnancy. Marital status, parity, location of residence (rural v. urban), smoking during pregnancy and maternal influenza risk status were determinants of maternal vaccine receipt. The odds of preterm birth was lower among infants of vaccinated women than among those of nonvaccinated women (adjusted odds ratio [OR] 0.75, 95% confidence interval [CI] 0.60–0.94). The rate of low-birth-weight infants was also lower among vaccinated women (adjusted OR 0.73, 95% CI 0.56–0.95).

Interpretation:

Despite current guidelines advising all pregnant women to receive the seasonal influenza vaccine, influenza vaccination rates among pregnant women in our cohort were low in the aftermath of the 2009 H1N1 pandemic. This study and others have shown an association between maternal influenza vaccination and improved neonatal outcomes, which supports stronger initiatives to promote vaccination during pregnancy.Influenza viruses are the leading cause of serious wintertime respiratory morbidity worldwide. Several studies investigating the effects of influenza-related illness during pregnancy have shown a strong impact on the health of pregnant women in terms of increased rates of hospital admission because of respiratory illness.13 Schanzer and colleagues2 found that pregnant women in Canada were at increased risk of influenza-related hospital admission when compared with nonpregnant women of similar age and health status. In addition, influenza-related illness during pregnancy may have a negative impact on neonatal outcomes. A study in Nova Scotia, Canada, showed that infants whose mothers were admitted to hospital because of respiratory illness during influenza season while pregnant were more likely to be small for gestational age and to have lower mean birth weight.4By 2007, the cumulative evidence from these and other studies was compelling enough for advisory boards in Canada to recommend routine influenza vaccination for all pregnant women, including those without medical comorbidities.5 Despite these recommendations, seasonal vaccination rates among pregnant women have remained low. In a cohort of pregnant women who delivered at the IWK Health Centre, Halifax, from 2006 to 2009, only 20% had received the vaccine during their pregnancy.6 Increased vaccination rates among pregnant women were reported for the 2009 H1N1 pandemic year,7 but it is unknown whether this has translated into higher rates of seasonal influenza vaccination since then. Studies have shown that concern about vaccine safety is the most commonly cited reason for refusing the vaccine,8,9 despite much evidence showing it to be safe in pregnancy.10 A recommendation from a maternity care provider has been shown to be a key factor in increasing vaccination rates.11,12In light of the growing evidence that influenza vaccination during pregnancy has benefits for both the mother and the infant,1318 we evaluated rates of seasonal influenza vaccination among pregnant women in the 2 nonpandemic influenza seasons (2010/11 and 2011/12) following the 2009 H1N1 pandemic. We also assessed whether neonatal outcomes differed between women who received the vaccine during pregnancy and those who did not.  相似文献   
148.
Both mutualistic and biotrophic pathogenic fungi rely on living host plants for growth and reproduction and must modify host cell structure and function for successful infection. The deployment of a diverse set of secreted virulence determinants referred to as 'effectors', many of which are directly delivered into the host cell, is postulated to be the key to host infection. This review provides a snapshot of the current progress in fungal effector biology. Recent genome sequencing of rust and powdery mildew obligate biotrophs has provided insight into the repertoires of potential effectors of these highly specialised pathogens. Identification of the first host-translocated effectors from mutualistic fungi has revealed that these fungi also manipulate host cells through effectors. The biological activities of some fungal effectors are just beginning to be revealed, while much uncertainty still surrounds the mechanisms of transport into host cells.  相似文献   
149.
The metabolic theory of ecology (MTE) predicts the effects of body size and temperature on metabolism through considerations of vascular distribution networks and biochemical kinetics. MTE has also been extended to characterise processes from cellular to global levels. MTE has generated both enthusiasm and controversy across a broad range of research areas. However, most efforts that claim to validate or invalidate MTE have focused on testing predictions. We argue that critical evaluation of MTE also requires strong tests of both its theoretical foundations and simplifying assumptions. To this end, we synthesise available information and find that MTE's original derivations require additional assumptions to obtain the full scope of attendant predictions. Moreover, although some of MTE's simplifying assumptions are well supported by data, others are inconsistent with empirical tests and even more remain untested. Further, although many predictions are empirically supported on average, work remains to explain the often large variability in data. We suggest that greater effort be focused on evaluating MTE's underlying theory and simplifying assumptions to help delineate the scope of MTE, generate new theory and shed light on fundamental aspects of biological form and function.  相似文献   
150.
One-carbon metabolism is a network of metabolic pathways, disruption of which has been associated with cancer and other pathological conditions. Biomarkers of these pathways include homocysteine (HCY), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH). A better understanding of the relationships between these biomarkers is needed for their utilization in research. This study investigated the relationships between fasting concentrations of plasma HCY, SAM, SAH and the ratio of SAM:SAH, and serum folate, vitamin B(12) and creatinine in a healthy adult population. A cross-sectional study recruited 678 volunteers; only subjects with complete data (n = 581) were included in this analysis. Correlations were used to examine bivariate relationships among the biomarkers and multivariate linear regression determined independent relationships with HCY, SAM and SAH treated as dependent variables in separate models. Multivariate logistic regression examined determinants of a low SAM:SAH ratio (defined as having a SAM:SAH ratio in the bottom quartile and SAH value in the top quartile). HCY correlated inversely with folate and vitamin B(12) and weakly correlated with SAH and creatinine. Both SAM and SAH correlated with creatinine but were independent of serum folate and vitamin B(12). In multivariate analyses, folate, vitamin B(12), creatinine, sex and age were associated with HCY; age and creatinine were determinants of SAM, and sex and creatinine determinants of SAH. Finally, male sex and increasing creatinine levels were associated with having a low SAM:SAH ratio. Findings suggest that HCY, SAM and SAH are relatively independent parameters and reflect distinct aspects of one-carbon metabolism.  相似文献   
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