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441.
Jennifer Zavaleta Cheek Johanna Eklund Nikolas Merten Jeremy Brooks Daniel C. Miller 《Conservation biology》2023,37(4):e14071
Knowledge of what conservation interventions improve biodiversity outcomes, and in which circumstances, is imperative. Experimental and quasi-experimental methods are increasingly used to establish causal inference and build the evidence base on the effectiveness of interventions, but their ability to provide insight into how and under what conditions an intervention should be implemented to improve biodiversity outcomes faces limitations. A suite of attribution methods that leverage qualitative methods for causal inference is available but underutilized in conversation impact evaluation. This article provides a guide to 5 such qualitative attribution methods: contribution analysis, process tracing, realist evaluation, qualitative comparative analysis, and most significant change. It defines and introduces each method and then illustrates how they could be applied through a case study of community conservancies in Namibia. This guide provides examples of how qualitative attribution methods can advance knowledge of what works, in which contexts, and why in biodiversity conservation. 相似文献
442.
David Eilam Pazit Zadicario Tom Genossar Joel Mort 《Behavioral ecology and sociobiology》2012,66(6):959-968
Social animals behave collectively in order to maintain a cohesive group. This collective behavior is often led by a few individuals of specific gender, social rank, or spatial physical location in the group (i.e., perimeter or front). We examined how individual social voles (Microtus socialis) in same-gender compared with mixed-gender groups respond to an owl attack. We found that anxiety level, as measured by the time that each individual spent in less-sheltered sectors (open arms of elevated plus-maze and center of open arena), was affected by both the social context and the gender of the tested individuals. While both female and male voles generally reduced their activity in the open following owl attack, males in mixed-gender groups were exceptional in dichotomizing into those that spent a short period and those that spent a long period in the open arms of the plus-maze. Based on the similar responses of the same-gender groups, we suggest that anxiety is contagious, and based on the lower anxiety level of the mixed-gender groups, we suggest that natural groups that comprise both males and females are better able to cope with life-threat compared with same-gender groups. Finally, we suggest that the differential responses of males in the mixed-gender groups were due to a few males that displayed a low level of anxiety. These males were probably individuals of high social rank, and their response reflects their natural protective role, as previously described in social voles. 相似文献
443.
Manuel Soler Liesbeth de Neve Gianluca Roncalli Elena Macías-Sánchez Juan Diego Ibáñez-Álamo Tomás Pérez-Contreras 《Behavioral ecology and sociobiology》2014,68(2):333-342
The post-fledging period is a critical phase for juvenile survival, and parental care provided during this period is a key component of avian reproductive performance. Very little is known about the relationships between foster parents and fledglings of brood parasites. Here, we present the results of a 5-year study about the relationships between fledglings of the non-evictor brood parasitic great spotted cuckoo (Clamator glandarius) and its magpie (Pica pica) foster parents. Sometimes, great spotted cuckoo and magpie nestlings from the same nest can fledge successfully, but most often parasitic nestlings outcompete host nestlings and only cuckoos leave the nest. We have studied several aspects of cuckoo post-fledging performance (i.e. feeding behaviour, parental defence and fledgling survival) in experimental nests in which only cuckoos or both magpie and cuckoo nestlings survived until leaving the nest. The results indicate that great spotted cuckoo fledglings reared in mixed broods together with magpie nestlings were disadvantaged by magpie adults with respect to feeding patterns. Fledgling cuckoos reared in mixed broods were fed less frequently than those reared in only cuckoo broods, and magpie adults approached less frequently to feed cuckoos from mixed broods than cuckoos from only cuckoo broods. These results imply that the presence of host's own nestlings for comparison may be a crucial clue favouring the evolution of fledgling discrimination; and furthermore, that the risk of discrimination at the fledgling stage probably is an important selection pressure driving the evolution of the arms race between brood parasites and their hosts. 相似文献
444.
Unsightly and environmentally damaging debris is an ever present problem for waterways and beaches around the world. This debris has numerous sources, and is comprised of materials ranging from metal and wood to plastics and paper. the aesthetic, economic, and environmental impacts of debris have been well documented over the past several years. in an effort to control the release of trash and debris into our waters, there are many activities ongoing in the US. One such activity is a coordinated effort between the US Environmental Protection Agency (EPA), other federal Agencies (National Oceanic and Atmospheric Administration (NOAA), United States Coast Guard (USCG), United States Navy (USN), National Park Service (NPS), Department of Interior (DOI)), industry (the Society of the Plastics Industry, INC. (SPI)), environmental, and local groups. This paper describes the results of field assessments, and the other activities undertaken by EPA as part of this coordinated effort to control the release of debris to our nation's waterways. 相似文献
445.
446.
Tom Hart Richard Mann Tim Coulson Nathalie Pettorelli Phil Trathan 《Marine Biology》2010,157(7):1543-1553
Recording the activity of animals as they migrate or forage has proven hugely advantageous to understanding how animals use
their environment. Where animals cannot be directly observed, the problem remains of how to identify distinct behaviours that
represent an animal’s decision-making process. An excellent example of this problem is that of foraging penguins, which travel
to sea to find prey to provision their young. Without direct sampling of the prey field, we cannot calibrate patterns of movement
with prey capture, and therefore we cannot determine how different activities link to decision-making. To overcome this, we
use a hidden markov model (HMM), which is a machine-learning technique that seeks to identify the underlying states of a system
from observable outputs. We apply HMM to determine classes of behaviour from repetitive dives. We take dive data from 103
breeding macaroni penguins at Bird Island, South Georgia, for which we have measures of weight gain over a trip. We identify
two classes of behaviour; those of short-shallow and long-deep dives. Using these two behaviours, we calculate the transition
probabilities between these states and analyse these data to determine what predicts variation in the transition probabilities.
We found that the stage of reproduction during a season, the sex and year of an individual influenced the probability of transition
between long-deep and short-shallow sequential dives. We also found differences in the hourly transition rates between the
four reproductive stages (incubation, broodguard, crèche and premoult) over a daily cycle. We conclude that this application
of HMMs for behavioural switching is potentially useful for other species and other types of recorded behaviour. 相似文献
447.
We estimated silicate uptake kinetics for 8 spring diatom species using a model based on time series measurements of the depletion
of dissolved silicate (DSi) and increases in biomass. Furthermore, the carbon: nitrogen: silicate stoichiometric relationships
and maximum growth rates were determined. Differences in DSi uptake kinetics and maximum growth rate were distinct among the
species. All the most common diatom species (Chaetoceros wighamii, Pauliella taeniata, Skeletonema costatum and Thalassiosira baltica) were relatively lightly silicified and had variable but relatively low half-saturation constants (K
s
), indicating that they are well adapted to low DSi concentrations. The less common Diatoma tenuis and Nitzschia frigida had higher K
s
values, suggesting that they are more vulnerable to DSi limitation. The much used nitrogen:silicate ratio of 1 for marine
diatom biomass was too low for most of the examined species, while a ratio of 2–3 seems to be more appropriate for these Baltic
Sea species. 相似文献
448.
Green Treefrogs (Hyla cinerea) were captured, marked, measured and released at an urban study site in Lafayette, LA, during the 2004 and 2005 breeding seasons. A statistical method based on a generalization of the hypergeometric distribution was used to derive weekly time-series estimates of the population sizes. To describe the population dynamics, a stage structured mathematical model was developed and compared to time-series obtained from the weekly population estimates study using a least-squares approach. Two fitting experiments were done: (1) Using uniform distribution for the birth rate during the breeding season; (2) Using a birth rate distributed according to weekly data on frog calling intensity. Although both model-to-data fits look very promising during the years 2004 and 2005 and result in similar inherent survivorship rates for the tadpoles, juvenile and adult frogs, the fit that uses the calling data predicts a lower number of tadpoles and frogs in the long term than the one that uses uniform birth distribution. The parameter estimates resulting from these fitting experiments are used in the context of stochastic simulations to derive extinction and persistence probabilities for this population. Due to the oscillatory dynamics (with high amplitude) evidenced by the capture-recapture data and corroborated by the model, it is suggested that anuran monitoring efforts should take into account the natural intra-annual variation in population size. 相似文献
449.
Landfills have historically been seen as the ultimate solution for storing waste at minimum cost. It is now a well-known fact that such deposits have related implications such as long-term methane emissions, local pollution concerns, settling issues and limitations on urban development. Landfill mining has been suggested as a strategy to address such problems, and in principle means the excavation, processing, treatment and/or recycling of deposited materials. This study involves a literature review on landfill mining covering a meta-analysis of the main trends, objectives, topics and findings in 39 research papers published during the period 1988-2008. The results show that, so far, landfill mining has primarily been seen as a way to solve traditional management issues related to landfills such as lack of landfill space and local pollution concerns. Although most initiatives have involved some recovery of deposited resources, mainly cover soil and in some cases waste fuel, recycling efforts have often been largely secondary. Typically, simple soil excavation and screening equipment have therefore been applied, often demonstrating moderate performance in obtaining marketable recyclables. Several worldwide changes and recent research findings indicate the emergence of a new perspective on landfills as reservoirs for resource extraction. Although the potential of this approach appears significant, it is argued that facilitating implementation involves a number of research challenges in terms of technology innovation, clarifying the conditions for realization and developing standardized frameworks for evaluating economic and environmental performance from a systems perspective. In order to address these challenges, a combination of applied and theoretical research is required. 相似文献
450.