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101.
Genetic Analysis of the Endangered Island Endemic Malacothamnus fasciculatus (Nutt.) Greene var. nesioticus (Rob.) Kearn. (Malvaceae) 总被引:2,自引:0,他引:2
Susan M. Swensen Gerard J. Allan Melanie Howe Wayne J. Elisens Steven A. Junak Loren H. Rieseberg 《Conservation biology》1995,9(2):404-415
Isozyme, randomly amplified polymorphic DNA, and ribosomal DNA analyses were used to evaluate the genetic distinctness and diversity of the endangered island endemic Malacothamnus fasciculatus var. nesioticus (Santa Cruz Island bush mallow). Analysis of amplified DNA profiles and electrophoretic data indicates that var. nesioticus is genetically distinct from other varieties within the species. No isozyme or amplified DNA variation was detected among individuals of nesioticus populations, but restriction site analysis of ribosomal DNA revealed the presence of three closely related genotypes within one of the nesioticus populations. Apparent clonal structuring was found in both nesioticus populations and in one mainland population, var. nuttallli . Results from these analyses provide the background necessary for the design of conservation efforts with recovery goals that insure the long-term survival of Malacothamnus fasciculatus var. nesioticus . 相似文献
102.
Increased participation by mothers in the labour force may exert a negative effect on working mothers themselves (e.g. interrole conflict) and influence the marital relationship negatively. Recent research suggests that not all individuals experiencing psychological distress suffer psychological strain (e.g. marital discord). Rather, variables such as social support moderate negative effects of psychological stressors. To test this, sixty-four employed mothers (M age = 36 years) completed interrole conflict and spouse support scales. Marital satisfaction, verbal and nonverbal communication were the criteria operationalized to assess marital functioning. Using moderated multiple regression analyses, interrole conflict and spouse support predicted marital satisfaction and verbal communication significantly. In addition, spouse support may moderate negative effects of interrole conflict on marital satisfaction and verbal communication. With regard to nonverbal communication, spouse support was both a significant main effect and possibly a moderator of interrole conflict. The role of spouse support, conceptual and treatment implications, and future research priorities are identified. 相似文献
103.
Melanie?MassaroEmail author Lloyd?S.?Davis John?T.?Darby 《Behavioral ecology and sociobiology》2003,55(2):169-175
The handicap principle suggests that ornamental traits that function as honest signals in mate selection must be costly to be effective. We evaluated in the sexually monochromatic yellow-eyed penguin (Megadyptes antipodes) whether the carotenoid-derived plumage and eye coloration predicts parental quality and whether males and females within pairs mate assortatively in relation to these carotenoid-derived ornaments. In addition, we investigated whether age or body condition was related to the coloration of the ornamental traits. In yellow-eyed penguins, parental quality of males and females was predicted by eye and head plumage coloration. Even when we controlled for gender- and age-specific differences, eye and head plumage coloration reflected honestly parental quality. Males and females mated assortatively in relation to these ornamental traits. While age influenced coloration of both the eye and head plumage, body condition was related only to the saturation of plumage coloration. These results provide evidence that the carotenoid-derived ornaments in yellow-eyed penguins reflect the parental abilities of birds and, therefore, may be costly signals. Potentially, female and male yellow-eyed penguins could use eye and plumage coloration as an indirect cue in assessing age and quality of individual birds during mate choice. This is only the second study to examine plumage coloration in relation to sexual selection in penguins, while conspicuous ornamental traits in other species of penguin beg the question whether they also play a role in sexual selection.Electronic Supplementary Material Supplementary material is available in the online version of this article at Communicated by C.R. Brown 相似文献
104.
In designing a photocatalytic oxidation (PCO) system for a given air pollution source, destruction rates for volatile organic compounds (VOCs) are required. The objective of this research was to develop a systematic method of predicting PCO rate constants by correlating rate constants with physical-chemical characteristics of compounds. Accordingly, reaction rate constants were determined for destruction of volatile organics over a titanium dioxide (TiO2) catalyst in a continuous mixed-batch reactor. It was found that PCO rate constants for alkanes and alkenes vary linearly with gas-phase ionization potential (IP) and with gas-phase hydroxyl radical reaction rate constant. The correlations allow rates of destruction of compounds not tested in this research to be predicted based on physical-chemical characteristics. 相似文献
105.
Melanie Schubert Carsten Schradin Heiko G. Rödel Neville Pillay David O. Ribble 《Behavioral ecology and sociobiology》2009,64(2):257-264
Mate guarding is predicted to be one of the driving forces for the evolution of monogamy, but supporting evidence in free-living
mammals is rare. The goals of our study were three-pronged. First, we tested if mate guarding, measured as intrapair distance,
occurs as a behavioral tactic in round-eared sengis (Macroscelides proboscideus), a socially monogamous species lacking paternal care and in which females breed asynchronously, producing 2–3 litters during
an 8-month long breeding season. Second, we determined if mate guarding involves costs which we identified as changes in male
body mass. Third, we investigated whether variation in individual investment in mate guarding depended on the males’ body
mass and the number of neighboring males. Field data were collected in a semidesert in South Africa using radio-tracking,
trapping, and direct observations during three successive breeding seasons. Mate guarding strongly depended on the females’
reproductive state, and all males started to guard their mates prior to and during estrus, as exemplified by reduced intrapair
distance. Mate guarding incurred costs: overall, males lost about 5% of body mass. Male body mass loss and initial body mass
were negatively related to the intensity of precopulatory mate guarding. Furthermore, during estrus intrapair distance was
inversely correlated with the number of neighboring males. The results show that mate guarding is the predominant male tactic
in round-eared sengis. However, since mate guarding imposed costs, males may balance benefits and costs associated with guarding
by varying their effort in relation to their physical capabilities and the competitive environment. 相似文献
106.
Time in environmental science continues to be almost neglected. In connection with rising ecological problems long-term research, as is necessary for the evaluation and prediction of environmental conditions, seems to be an exception. Complex ecosystems, e.g. terrestrial and marine systems, however, are characterized by long lasting natural time-scales which must be taken into account by analyzing them. In this context the role of time in ecosystems research becomes important. Therefore, a data base was conceptualized that could take up the main characteristics of ecosystematic analyses. Annual research reports of ecosystem research centers were revised for taking them up into the data base. In this way it is possible to evaluate the pool of data on special aspects, especially on the time parameters of the analyses. One result — besides a partial unequality of the time scales in experiment and reality — is that long-term research in terrestrial ecosystems is very rare. The reasons for this are various, but cannot divert from the need for a greater consideration of longterm observation of the ecosystems. Otherwise the ecosystematic research will not be able to meet their tasks of evaluation and prediction. 相似文献
107.
Learning after a disaster is crucial in creating more resilient places. However, many societies are repeatedly overwhelmed by disasters. This can be because of missed opportunities to learn in post‐disaster settings or because of actions implemented that seem to be highly relevant to recovery in the short term, but potentially constrain aspirations in the longer term. This paper assesses learning processes among state and non‐state actors and the ways in which these are bridged and scaled up to wider improvements in governance. Aiming to enrich understanding of post‐disaster learning, it explores different actors’ response actions after the earthquakes in Christchurch, New Zealand, in 2010 and 2011. On the one hand, ‘learning by doing’ is occurring, yet, on the other hand, systemic learning is hindered by mismatches between top‐down steering and bottom‐up initiatives. The study concludes that better linking and synergising of learning processes among different levels is vital for enhancing resilience in post‐disaster societies. 相似文献
108.
Collaborative problem solving has increasingly become important in the face of the complexities in the management of resources, including protected areas. The strategy undertaken by Girringun Aboriginal Corporation in north tropical Queensland, Australia, for developing co-management demonstrates the potential for a problem solving approach involving sequential initiatives, as an alternative to the more familiar negotiated agreements for co-management. Our longitudinal case study focuses on the development of indigenous ranger units as a strategic mechanism for the involvement of traditional owners in managing their country in collaboration with government and other interested parties. This was followed by Australia's first traditional use of marine resources agreement, and development of a multi-jurisdictional, land to sea, indigenous protected area. In using a relationship building approach to develop regional scale co-management, Girringun has been strengthening its capabilities as collaborator and regional service provider, thus, bringing customary decision-making structures into play to 'care for country'. From this evolving process we have identified the key components of a relationship building strategy, 'the pillars of co-management'. This approach includes learning-by-doing, the building of respect and rapport, sorting out responsibilities, practical engagement, and capacity-building. 相似文献
109.
110.
John S. Schwartz Melanie Dahle R. Bruce Robinson 《Journal of the American Water Resources Association》2008,44(4):879-886
Abstract: Siltation and subsequent biological impairment is a national problem prompting state regulatory agencies to develop sediment total maximum daily loads (TMDL) for many streams. To support TMDL targets for reduced sediment yield in disturbed watersheds, a critical need exists for stream assessments to identify threshold concentrations of suspended sediment that impact aquatic biota. Because of the episodic nature of stream sediment transport, thresholds should not only be a function of sediment concentration, but also of duration and dose frequency. Water quality sondes can collect voluminous amounts of turbidity data, a surrogate for suspended sediment, at intervals that can be used to characterize concentration, duration, and frequency of elevated turbidity events. To characterize turbidity sonde data in an ecologically relevant manner, a methodology for concentration‐duration‐frequency (CDF) curves was developed using turbidity doses that relate to different levels of biological impairment. To illustrate this methodology, turbidity CDF curves were generated for two sites on Little Pigeon River in the Great Smoky Mountains National Park, Tennessee, using over 30,000 sonde data measurements per site for a one‐year period. Utilizing a Poisson arrival approach, turbidity spikes were analyzed stochastically by observing the frequency and duration of recorded events over a turbidity level that relates to a biological dose response. An exponential equation was used to fit duration and frequency of a specified turbidity level to generate concentric‐shaped CDF curves, where at specific turbidities longer durations occurred less frequently and conversely shorter durations occurred more frequently. The significance of the equation fit to the data was accomplished with a Kolmogorov‐Smirnov goodness‐of‐fit test. Our findings showed that the CDF curves derived by an exponential function performed reasonable well, with most curves significant at a 95% confidence level. These CDF curves were then used to demonstrate how they could be used to assess biological impairment, and identify future research needs for improved development of sediment TMDLs. 相似文献