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31.
Captive breeding and reintroduction remain high profile but controversial conservation interventions. It is important to understand how such programs develop and respond to strategic conservation initiatives. We analyzed the contribution to conservation made by amphibian captive breeding and reintroduction since the launch of the International Union for Conservation of Nature (IUCN) Amphibian Conservation Action Plan (ACAP) in 2007. We assembled data on amphibian captive breeding and reintroduction from a variety of sources including the Amphibian Ark database and the IUCN Red List. We also carried out systematic searches of Web of Science, JSTOR, and Google Scholar for relevant literature. Relative to data collected from 1966 to 2006, the number of species involved in captive breeding and reintroduction projects increased by 57% in the 7 years since release of the ACAP. However, there have been relatively few new reintroductions over this period; most programs have focused on securing captive‐assurance populations (i.e., species taken into captivity as a precaution against extinctions in the wild) and conservation‐related research. There has been a shift to a broader representation of frogs, salamanders, and caecilians within programs and an increasing emphasis on threatened species. There has been a relative increase of species in programs from Central and South America and the Caribbean, where amphibian biodiversity is high. About half of the programs involve zoos and aquaria with a similar proportion represented in specialist facilities run by governmental or nongovernmental agencies. Despite successful reintroduction often being regarded as the ultimate milestone for such programs, the irreversibility of many current threats to amphibians may make this an impractical goal. Instead, research on captive assurance populations may be needed to develop imaginative solutions to enable amphibians to survive alongside current, emerging, and future threats. 相似文献
32.
There is a consensus that Marine Protected Area (MPA) performance needs regular evaluation against clear criteria, incorporating
counterfactual comparisons of ecological and socio-economic performance. However, these evaluations are scarce at the global
level. We compiled self-reports from managers and researchers of 78 coral reef-based MPAs world-wide, on the conservation
and welfare improvements that their MPAs provide. We developed a suite of performance measures including fulfilment of design
and management criteria, achievement of aims, the cessation of banned or destructive activities, change in threats, and measurable
ecological and socio-economic changes in outcomes, which we evaluated with respect to the MPA’s age, geographical location
and main aims. The sample was found to be broadly representative of MPAs generally, and suggests that many MPAs do not achieve
certain fundamental aims including improvements in coral cover over time (in 25% of MPAs), and conflict reduction (in 25%).
However, the large majority demonstrated improvements in terms of slowing coral loss, reducing destructive uses and increasing
tourism and local employment, despite many being small, underfunded and facing multiple large scale threats beyond the control
of managers. However spatial comparisons suggest that in some regions MPAs are simply mirroring outside changes, with demonstrates
the importance of testing for additionality. MPA benefits do not appear to increase linearly over time. In combination with
other management efforts and regulations, especially those relating to large scale threat reduction and targeted fisheries
and conflict resolution instruments, MPAs are an important tool to achieve coral reef conservation globally. Given greater
resources and changes which incorporate best available science, such as larger MPAs and no-take areas, networks and reduced
user pressure, it is likely that performance could further be enhanced. Performance evaluation should test for the generation
of additional ecological and socio-economic improvements over time and compared to unmanaged areas as part of an adaptive
management regime. 相似文献
33.
34.
Elaine K. Harding 《Conservation biology》2003,17(3):651-651
35.
Brian D. Fox Brian P. Bledsoe Eleanor Kolden Matthew C. Kondratieff Christopher A. Myrick 《Journal of the American Water Resources Association》2016,52(2):420-442
Whitewater parks (WWPs) typically consist of instream structures that enhance recreational boating by constricting flow into a steep chute that generates a hydraulic jump in a downstream pool. Concerns have been raised that high velocities resulting from WWPs may be inhibiting fish movement during critical life stages. We evaluated the effects of WWPs on upstream fish passage by concurrently monitoring fish movement and hydraulic conditions at three WWP structures and three adjacent natural control (CR) sites in a wadeable river in northern Colorado. Fish movement was tracked with a network of Passive Integrated Transponder antennas over a 14‐month period. Individual fishes (n = 1,639), including brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss), were tagged and released within WWP and CR sites. Detailed hydraulic conditions occurring during the study period were evaluated with a fully 3D model. Results reveal the WWPs monitored in this study are not a complete barrier to upstream salmonid movement, but differences in passage efficiency from release location range from 29 to 44% in WWP sites and 37 to 63% for CR sites and the suppression of movement is related to body length. Small numbers of monitored nonsalmonids were inadequate to directly observe effects on their movement; however, it is highly probable that movement of smaller native fishes is also suppressed. Hydraulic modeling helps in the design of WWP structures that protect fish passage. 相似文献
36.
37.
Only in several controlled studies have organizational or situational stressors (in contrast to individuals) been targeted for change in order to reduce occupational stress. This study evaluates the impact of an intervention which was based on organizational development, action research and Karasek's job strain model. Employee committees conducted problem diagnosis, action planning, and action taking in two departments in a public agency. Waiting list control departments and pre- post- and follow-up assessment were utilized. Results indicated a mixed impact of the intervention in one department, but a negligible or negative impact in the other. Obstacles to the effective implementation of the intervention strategy are discussed. These included a limited focus for the committees (department-wide rather than agency-wide), the negative impact of a major agency reorganization, and the lack of a more formal management and labour commitment to maintaining the stress reduction and organizational change process. 相似文献
38.
Helper contributions to reproductive success in the splendid fairy-wren (Malurus splendens) 总被引:1,自引:0,他引:1
Summary In Malurus splendens, helpers were present in 65% of 226 group-years with at least one helper female in 37% of group-years. Most females helped for only one year, while many males did so for at least two years. Most were offspring of one or both present breeders, and in 53% of helper-years, helped both parents. For 159 helpers of known age and parentage, the mean coefficient of relatedness to the offspring was 0.47. Novice females with or without helpers produced fewer fledglings per season than females with one year breeding experience and the same level of help. Helpers did not affect production of fledglings per year by females with one year of experience. Females with two or more years experience and at least two helpers produced more fledglings than equivalent birds with one or no helpers. Experience and helpers have little effect on production of fledglings per nest but they lead to more females renesting after a first brood has been raised. Fewer than 20% of novices renest after fledging one brood, while for females with at least two years experience, the percent renesting after success is 40% with no help, 56% with one helper and 69% with 2 or more helpers. Experienced females begin their first clutch earlier than novices, and helpers reduce the time to renest after success from 66 days for an experienced female with no helpers to 50 days for females with at least two years experience and two or more helpers. Breeding females with helpers survive better (76%) than those with no helpers (55%), and helpers thus gain future indirect fitness. Despite their close relatedness to breeders and offspring, in only 19% of group-years did helpers increase their indirect fitness from an increase in productivity. 相似文献
39.
Summary In a population of the splendid fairy-wren Malurus splendens, we describe 202 intrusions by solitary adult males in full breeding plumage into the territories of conspecifics. Intrusions were not secretive and although silent they involved conspicuous flight above the vegetation and several characteristic display elements, including petal-carrying. Fifteen intrusions were observed in the 2 months before eggs were laid, but the rest occurred during the period of nest-building and egg-laying when the breeding female was presumed to be fertile, and were by males from adjacent territories. A high level of extra-pair fertilization has previously been determined in this species and we interpret many of these intrusions as attempts by males to obtain extra-pair copulations (EPC); we call this activity philandering. The costs and benefits of EPC for males and females are discussed and the promiscuous mating strategy of M. splendens is contrasted with the persistent social pairing in stable groups of this long-lived cooperatively breeding species.Offprint requests to: I. Rowley 相似文献
40.
Polychlorinated biphenyl (PCB) uptake by marine phytoplankton 总被引:1,自引:0,他引:1
The time-courses of uptake for 2,4,5,2,5-pentachlorobiphenyl (PCB) by 11 marine phytoplankton species were measured and found to be rapid, with equilibration occurring within 0.5 to 2.0 h. These data were described with the empirical Freundlich adsorption isotherm. The relationship between cell density and accumulation of PCBs was also investigated. Concentration factors on a volume per volume basis ranged from 1.23x104 to 2.41x106 for the 11 algal species examined. These values are comparable in magnitude to factors reported previously for phytoplankton in natural marine systems. 相似文献