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211.
Anke Fischer Yitbarek Tibebe Weldesemaet Mikołaj Czajkowski Degu Tadie Nick Hanley 《Conservation biology》2015,29(4):1111-1121
In the face of fundamental land‐use changes, the potential for trophy hunting to contribute to conservation is increasingly recognized. Trophy hunting can, for example, provide economic incentives to protect wildlife populations and their habitat, but empirical studies on these relationships are few and tend to focus on the effects of benefit‐sharing schemes from an ex post perspective. We investigated the conditions under which trophy hunting could facilitate wildlife conservation in Ethiopia ex ante. We used a choice experiment approach to survey international trophy hunters’ (n = 224) preferences for trips to Ethiopia, here operationalized as trade‐offs between different attributes of a hunting package, as expressed through choices with an associated willingness to pay. Participants expressed strong preferences and, consequently, were willing to pay substantial premiums for hunting trips to areas with abundant nontarget wildlife where domestic livestock was absent and for arrangements that offered benefit sharing with local communities. For example, within the range of percentages considered in the survey, respondents were on average willing to pay an additional $3900 for every 10 percentage points of the revenue being given to local communities. By contrast, respondents were less supportive of hunting revenue being retained by governmental bodies: Willingness to pay decreased by $1900 for every 10 percentage points of the revenue given to government. Hunters’ preferences for such attributes of hunting trips differed depending on the degree to which they declared an interest in Ethiopian culture, nature conservation, or believed Ethiopia to be politically unstable. Overall, respondents thus expressly valued the outcomes of nature conservation activities—the presence of wildlife in hunting areas—and they were willing to pay for them. Our findings highlight the usefulness of insights from choice modeling for the design of wildlife management and conservation policies and suggest that trophy hunting in Ethiopia could generate substantially more financial support for conservation and be more in line with conservation objectives than is currently the case. 相似文献
212.
Abstract: The mandate to increase endangered salmon populations in the Columbia River Basin of North America has created a complex, controversial resource‐management issue. We constructed an integrated assessment model as a tool for analyzing biological‐economic trade‐offs in recovery of Snake River spring‐ and summer‐run chinook salmon (Oncorhynchus tshawytscha). We merged 3 frameworks: a salmon‐passage model to predict migration and survival of smolts; an age‐structured matrix model to predict long‐term population growth rates of salmon stocks; and a cost‐effectiveness analysis to determine a set of least‐cost management alternatives for achieving particular population growth rates. We assessed 6 individual salmon‐management measures and 76 management alternatives composed of one or more measures. To reflect uncertainty, results were derived for different assumptions of effectiveness of smolt transport around dams. Removal of an estuarine predator, the Caspian Tern (Sterna caspia), was cost‐effective and generally increased long‐term population growth rates regardless of transport effectiveness. Elimination of adult salmon harvest had a similar effect over a range of its cost estimates. The specific management alternatives in the cost‐effective set depended on assumptions about transport effectiveness. On the basis of recent estimates of smolt transport effectiveness, alternatives that discontinued transportation or breached dams were prevalent in the cost‐effective set, whereas alternatives that maximized transportation dominated if transport effectiveness was relatively high. More generally, the analysis eliminated 80–90% of management alternatives from the cost‐effective set. Application of our results to salmon management is limited by data availability and model assumptions, but these limitations can help guide research that addresses critical uncertainties and information. Our results thus demonstrate that linking biology and economics through integrated models can provide valuable tools for science‐based policy and management. 相似文献
213.
Assessing the potential of native tree species for carbon sequestration forestry in Northeast China 总被引:2,自引:0,他引:2
Although the native forests of China are exceptionally diverse, only a small number of tree species have been widely utilized in forest plantations and reforestation efforts. We used dendrochronological sampling methods to assess the potential growth and carbon sequestration of native tree species in Jilin Province, Northeast China. Trees were sampled in and near the Changbaishan Biosphere Reserve, with samples encompassing old-growth, disturbed forest, and plantations. To approximate conditions for planted trees, sampling focused on trees with exposed crowns (dominant and co-dominant individuals). A log-linear relationship was found between diameter increment and tree diameter, with a linear decrease in increment with increasing local basal area; no significant differences in these patterns between plantations and natural stands were detected for two commonly planted species (Pinus koraiensis and Larix olgensis). A growth model that incorporates observed feedbacks with individual tree size and local basal area (in conjunction with allometric models for tree biomass), was used to project stand-level biomass increment. Predicted growth trajectories were then linked to the carbon process model InTEC to provide estimates of carbon sequestration potential. Results indicate substantial differences among species, and suggest that certain native hardwoods (in particular Fraxinus mandshurica and Phellodendron amurense), have high potential for use in carbon forestry applications. Increased use of native hardwoods in carbon forestry in China is likely to have additional benefits in terms of economic diversification and enhanced provision of "ecosystem services", including biodiversity protection. 相似文献
214.
Saltwater fishing tournaments in the United States are generally not regulated nor are there different fishing regulations
for tournament and nontournament anglers. Although much is known about those who participate in fishing tournaments in terms
of their fishing motivations, attitudes, and characteristics, much less is known at the angler population level regarding
their preferences for tournament opportunities. Using a stated preference choice model with hypothetical scenarios to simulate
participation choices and understand preferences, study objectives were to identify angler preferences for various types of
tournament fishing “products.” Four tournament policy characteristics were investigated: promotion of catch and release, bait
restrictions, whether a percentage of the tournament entrance fee should go to support fishery management activities, and
whether a tournament should be a nonprofit or profit-making venture. Three expectation attributes were inserted: tournament
size, trip cost per day, and whether a tournament is family friendly. We sent seven different versions of the mail questionnaire
to 1,633 anglers. Of 795 returns, 648 were used for estimating conditional logit models. Analysis indicated that a scenario
with no management interventions was not most preferred. Anglers most preferred a conservation-oriented option that introduced additional management measures. Overall,
scenarios with management interventions were more favored than the status quo situation (with no management interventions).
Although respondents showed reluctance to adopt other management-related options, results generally indicated they were increasingly
concerned with sustainability of fish stocks and potential conflicts between tournament and nontournament users and preferred
tournament products that reflect these concerns. 相似文献
215.
Fee-fishing involves paying a fee for the privilege of fishing a body of water where fish populations are enhanced by stocking
fish. Past literature on this activity has focused more on the operation of the enterprise and management of the fish than
the people and site characteristics. The objectives of the study were to profile anglers and describe their site/management
preferences. This study utilized an on-site interview and mail-back questionnaire at fee-fishing establishments in West Virginia
(n = 212). Factor analysis of desired recreation experiences yielded five factors: Experience nature & adventure, Stress release & relaxation, Trophy fishing, Escape, and Family time. Cluster analysis showed that these anglers can be segmented into two distinct clusters, differing by sociodemographic characteristics,
fishing behavior, and site/management preferences. The findings from this study provide baseline data to aid public resource
managers and fee-fishing business owners in determining how to provide satisfying outdoor experiences and deliver desired
services on-site. Future research will be needed from additional fee-fishing sites to obtain more detail about this outdoor
recreation cohort and be able to generalize to a larger population of participants. 相似文献
216.
This research surveyed human-impacted littoral forests in southeastern Madagascar to determine (i) how forest structural features, indicative of human impact, are related to total, utilitarian, and endemic tree diversity; (ii) the distribution, abundance, and demographics of tree species groups (i.e., total, useful, endemic) across the landscape; and (iii) the amount of basal area available per human use category. We also use these data to consider issues of sustainable use and how human impact may influence littoral forest tree community composition across the landscape. Within 22 transects of 400 m2 each, we recorded a total of 135 tree species and 2155 individuals. Seventy-nine species (58%) were utilitarian and 56 (42%) were nonutilitarian species. Of the 2155 individuals, 1827 (84%) trees were utilitarian species. We recorded 23 endemic species (17% of the total species) and 17 (74%) of these were utilitarian species. Basal area was significantly correlated with Shannon Weiner Index values for total (r = 0.64, P < 0.01), utilitarian (r = 0.58, P < 0.01), and endemic tree diversity (r = 0.85, P < 0.01). Basal area was significantly correlated with the Simpson’s index values for the endemic species (r = 0.74, P < 0.01). These correlations suggest that endemic tree species, of high global conservation value, may be the species group most influenced by changes in forest structure. Utilitarian species constituted 84% of the total basal area. The use category contributing the highest amount of basal area to the landscape was firewood. The results presented herein demonstrate that the landscape of southeastern Madagascar, commonly perceived as degraded, retains high value for both global conservation purposes and for local livelihoods. Thus, valuable opportunities may exist for developing conservation incentives that leverage both global and local conservation needs. 相似文献
217.
N = 406), highlight some important issues concerning the design and management of wildland recreation environments that are
primarily used for mountain biking. For example, bikers were found to significantly prefer water bars above all other tested
soil erosion management techniques; trail erosion factors, including the presence of rocks, roots, and gullies, all added
to biking experiences on average; trail design factors, such as the presence of turns, bumps, jumps, and obstacles, all added
to biking experiences in general. These findings were used to address questions that resource managers should consider when
striving to effectively manage wildland recreation areas primarily used for mountain biking. 相似文献
218.
Extending livestock grazing to the steep slopes has led to unstable grazing systems in the East African Highlands, and new
solutions and approaches are needed to ameliorate the current situation. This work was aimed at studying the effect of livestock
grazing on plant attributes and hydrological properties. The study was conducted from 1996 to 2000 at the International Livestock
Research Institute at Debre Ziet Research Station. Two sites were selected: one at 0–4% slope, and the other at 4–8% slope.
The treatments were: (1) no grazing (control); (2) light grazing, 0.6 animal unit months per hectare (aum/ha); (3) moderate
grazing, 1.8 aum/ha; (4) heavy grazing, 3.0 aum/ha; (5) very heavy grazing, 4.2 aum/ha; (6) initially plowed and continuously
very heavily grazed, 4.2 aum/ha. The result showed that species richness, infiltration rate, bare ground, and soil loss significantly
varied with grazing pressure. Species richness was higher in grazed plots compared to nongrazed plots. Biomass yield improved
on heavily grazed plots as cow dung accumulated over years. Cynodon dactylon plant species persisted with livestock grazing pressure in both sites. Infiltration rate improved and soil erosion declined
in all treatments after the first year. 相似文献
219.
Understanding the problems of grazing land in vertisol areas and seeking long-lasting solutions is the central point where
mixed crop livestock is the second stay for the majority of the population. In order to understand this, the current study
was conducted at two sites, one with 0–4% slope and the other with 4–8% slope at Ginchi watershed, 80 km west of Addis Ababa,
Ethiopia. The specific objectives of the study were to quantify changes in plant species richness, biomass, plant cover, and
soil physical and hydrological properties. The grazing regimes were: moderate grazing (regulated), heavy grazing (free grazing),
and no grazing (closed to any grazing), which was considered the control treatment. The results showed that the biomass yield
in nongrazed plots was higher than in the grazed plots. However, the biomass yield in grazed plots improved over the years.
Species richness and percentage of dominant species attributes were better in medium grazed plots than the other treatments.
Soil compaction was higher in very heavily grazed plots than in nongrazed and medium-grazed plots. In contrast to that, the
soil water content and infiltration rate were better in nongrazed plots than in grazed plots. Soil loss in grazed plots decreased
with the increase of biomass yields and as the soil was more compacted by livestock trampling during the wet season. Finally
since the medium stocking rate is better in species richness and plant attributes, and lies between nongrazed and heavily
grazed plots in the rest of the measured parameters, it could be the appropriate stocking rate to practice by the smallholder
farmer. 相似文献
220.
Michael Martin Joel R. Hamilton Ken Casauant 《Journal of the American Water Resources Association》1992,28(4):673-680
ABSTRACT: The listing of the Snake-Columbia River salmon under the Endangered species Cut will lead to a set of river management changes aimed at species recovery. One measure almost certain to be implemented is a periodic river drawdown. A drawdown will speed fish migration downriver but will also temporarily close the river to barge transportation. Grain shippers in the region rely on the barge carriage to move a significant share of annual production to export elevators on the Lower Columbia. A number of other bulk commodities utilize barges as well. This study outlines the aggregate and distributional economic implications of a suspension of barge transportation resulting from a river drawdown. 相似文献