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961.
Shrimp trawling is common throughout the southeastern and Gulf of Mexico coasts of the USA and is the primary contributor
to fisheries discards in these regions. Tens of thousands of nearshore seabirds nest near shrimp trawling grounds in the USA,
but to date, there has been no assessment of the relationship between seabirds and shrimp trawlers. We examined the taxonomic
composition of bycatch, rate at which seabirds scavenged bycatch, and energy density of discarded bycatch in a nearshore commercial
shrimp fishery. Bycatch was primarily comprised of demersal fish that are not typically accessible to the plunge-diving and
surface-feeding seabirds that occur in the area. Hence, seabird diets in the region appear to be broadened taxonomically by
the availability of discards. Results from discard experiments indicated that 70% of the nearly 5,500 items discarded by hand
were scavenged by seabirds and that the fate of a discarded item was most strongly predicted by its taxonomic order. Laughing
gulls scavenged the greatest proportion of discards, although brown pelicans were the only species to scavenge more discards
than predicted based upon their abundance. Because this is the first such study in the region, it is difficult to ascertain
the extent or intensity of the impact that discards have on nearshore seabirds. Nonetheless, our results suggest that it will
be difficult for managers to clearly understand fluctuations in local seabird population dynamics without first understanding
the extent to which these species rely upon discards. This may be especially problematic in situations where seabird populations
are recovering following natural or anthropogenic stressors. 相似文献
962.
Predation is often considered as one of the most important biotic factor determining the success of exotic species. The freshwater amphipod Gammarus roeseli has widely colonized Western Europe, where it is frequently found in sympatry with the native species (Gammarus pulex). Previous laboratory experiments revealed that G. roeseli may have an advantage over G. pulex through differential predation by native fish (brown trout). Morphological anti-predator defences (spines) were found responsible for lower rates of predation on the invasive G. roeseli. Here, using both field surveys and laboratory experiments, we tested if a differential of predation exists with other fish predators naturally encountered by gammarids. The main predators present in our field site were nocturnal benthic feeders (mainly bullheads, Cottus gobio). Fish diet analysis showed that, compared to its global availability in the river, G. roeseli was less consumed than G. pulex. In the field, however, G. roeseli was found mainly in the aquatic vegetation whereas G. pulex was found in all habitat types. Laboratory experiments in microcosms revealed that G. roeseli was less prone to predation by C. gobio only when vegetation was present. Depending on the type of predator, the differential of predation could therefore be mediated by antipredator behaviour, and a better usage of refuges, rather than by morphological defences. 相似文献
963.
Barbro Ulén Mats Larsbo Johannes Koestel Qarin Hellner Maria Blomberg Pia Geranmayeh 《Ambio》2018,47(1):114-123
Assessing mitigation of phosphorus (P) leaching from subsurface drainage systems is challenging due to high spatial and temporal variation in leaching. Mean measured total P leaching from a clayey soil in an eight-year study period (four replicates per treatment) was (kg ha?1 year?1): 1.21 from shallow autumn tillage (ShT), 0.84 from unfertilised fallow (UF), 0.81 from conventional autumn ploughing (CT) and 0.57 from structure liming (SL–CT). Treatment was not significant using Richards–Baker flow index or a distance factor as covariate (p = 0.084 and 0.057). A tendency for lower leaching was obtained comparing SL-CT with ShT (p adjusted = 0.060 and 0.009 respectively). A combination of measures adapted to drainage conditions and clay content in different parts of the field is proposed since P leaching was approximately halved from an adjacent field (4.3 ha) in a three-year post-period compared with a three-year pre-period for structure liming the entire field and drainage system renovation plus structure lime drain backfilling. 相似文献
964.
Robins L 《Environmental management》2008,42(5):833-846
This paper aims to give practical meaning to ‘capacity building’ through (a) identifying a suite of practical measures, such
as mentoring or best practice guidelines, that have been shown to or are considered to build human, social, institutional,
and economic capital; (b) placing these measures within a broader systems framework; and (c) exploring stakeholder feedback
on specific measures to inform framework implementation. The 29 measures described provide actors, whether government or nongovernment,
with a suite of practical investment choices for building capacity. These measures are then clustered into eight groups according
to their primary purpose and placed within a systems framework. The framework provides a tool for actors with responsibilities
for or an interest in capacity building to inform more holistic and strategic targeting of effort and investment. Stakeholder
feedback gathered through surveys and workshops is subsequently reported to further inform implementation of specific measures
within the framework’s eight groupings. The framework presented may be built upon through the identification and inclusion
of further capacity building measures. The research is conducted within the context of decentralized governance arrangements
for natural resource management (NRM), with specific focus on Australia’s recently formalized 56 NRM regions and their community-based
governing boards as an informative arena of learning. Application of the framework is explored in the Australian setting through
the identification and comparison of measures supported and most preferred by four major stakeholder groups, namely board
members, regional NRM organization staff, policy/research interests, and Indigenous interests. The research also examines
stakeholder perceptions of capacity issues, and whether these issues are likely to be addressed through implementing their
preferred measures.
相似文献
Lisa RobinsEmail: |
965.
An Interpretive Study of Yosemite National Park Visitors’ Perspectives Toward Alternative Transportation in Yosemite Valley 总被引:1,自引:0,他引:1
White DD 《Environmental management》2007,39(1):50-62
The National Park Service (NPS) is increasingly focusing on alternative transportation systems in national parks to address
environmental and social problems arising from a historical reliance on personal automobiles as the primary means of visitor
access. Despite the potential advantages, alternative transportation may require a reorientation in the way that Americans
have experienced national parks since the advent of auto-tourism in the early twentieth century. Little research exists, however,
on visitor perspectives towards alternative transportation or the rationale underlying their perspectives. It remains unclear
how transportation systems affect visitors’ experiences of the park landscape or the factors influencing their travel behavior
in the parks. This report presents an interpretive study of visitor perspectives toward transportation management in the Yosemite
Valley area of Yosemite National Park, California. Qualitative analysis of 160 semi-structured interviews identified individual
psychological factors as well as situational influences that affect visitors’ behavior and perspectives. Individual psychological
factors include perceived freedom, environmental values and beliefs, prior experience with Yosemite National Park and other
national parks, prior experience with alternative transportation in national parks, and sensitivity to subjective perceptions
of crowding. Situational factors included convenience, access, and flexibility of travel modes, as well as type of visit,
type of group, and park use level. Interpretive communication designed to encourage voluntary visitor use of alternative transportation
should focus on these psychological and situational factors. Although challenges remain, the results of this study suggest
approaches for shaping the way Americans visit and experience their national parks to encourage environmental sustainability. 相似文献
966.
The Patagonian coast is considered a relatively pristine environment. However, studies conducted along coastal Patagonia have
showed hydrocarbon pollution mostly concentrated at ports that have fishing, oil loading, general merchant, and/or tourist
activities. A high value of total aliphatic hydrocarbons (TAH) was found at the Rawson fishing port (741 μg/g dw). In other
ports with and without petroleum-related activities, hydrocarbon values were approximately 100 μg/g dw. The highest values
for TAH and total aromatic hydrocarbons (TArH) were found in Faro Aristizábal, north of San Jorge gulf (1304 and 737 μg/g
dw, respectively). This is very likely the result of petroleum-related activities at the Comodoro Rivadavia, Caleta Cordova,
and Caleta Olivia ports located within this gulf. In other coastal areas away from potential anthropogenic sources, hydrocarbon
values were less than 2 and 3 μg/g dw for TAH and TArH, respectively. This review of published and unpublished information
suggests that ports are important oil pollution sources in the Patagonian coast. More detailed studies are needed to evaluate
the area affected by port activities, to understand the mechanisms of hydrocarbon distribution in surrounding environments,
and to assess bioaccumulation in marine organisms. Despite that some regulations exist to control oil pollution derived from
port and docked vessel activities, new and stricter management guidelines should be implemented. 相似文献
967.
Evolution of a Mediterranean Coastal Zone: Human Impacts on the Marine Environment of Cape Creus 总被引:1,自引:0,他引:1
This study presents an integrated analysis of the evolution of the marine environment and the human uses in Cape Creus, a
Mediterranean coastal area where intense commercial fisheries and recreational uses have coexisted over the last fifty years.
The investigation synthesizes the documented impacts of human activities on the marine environment of Cap de Creus and integrates
them with new data. In particular, the evolution of vulnerable, exploited species is used to evaluate the fishing impacts.
The effects of area protection through the establishment of a marine reserve in the late 1990s and the potential climate change
impacts are also considered. The evolution of the human uses is marked by the increasing socioeconomic importance of recreational
activities (which affect species and habitats) in detriment to artisanal and red coral fisheries (which principally affect
at a species level). Overall, populations of sedentary, vulnerable exploited species, hard sessile benthic invertebrates,
and ecologically fragile habitats, such as seagrass meadows, the coralligenous and infralittoral algal assemblages have been
the most negatively impacted by anthropogenic activities. Albeit human uses currently constitute the largest negative impact
on the marine environment of Cap de Creus, climate change is emerging as a key factor that could have considerable implications
for the marine environment and tourism activities. The establishment of the marine reserve appears to have had little socioeconomic
impact, but there is some evidence that it had some positive biological effects on sedentary, littoral fishes. Results demonstrate
that the declaration of a marine reserve alone does not guarantee the sustainability of marine resources and habitats but
should be accompanied with an integrated coastal management plan. 相似文献
968.
Whereas past research has treated co-management of common pool resources as if villagers and project implementing authorities
were the only relevant actors, numerous external factors beyond the control of these two partners create barriers to successful
co-management. This paper draws on discussions with Forest Department officials to examine the influence of these forces on
the outcomes of Joint Forest Management (JFM) in Tamil Nadu, India. An empirical inquiry into the operational aspects of JFM
indicates the important roles of political parties, powerful people, and other state institutions and functionaries as well
as the flow of foreign funding. Further, the strong demand by local people for socio-economic development interventions as
opposed to improvement of degraded forests belittles the role of the Forest Department relative to other departments. Numerous
other conditioning factors and relationships are explored. The authors call for reforms in public governance to allow better
participation of all the actors involved for this participatory management approach to succeed and sustain. 相似文献
969.
Kazuyuki Oshita Xiucui Sun Koji Kawaguchi Kenji Shiota Masaki Takaoka Kazutsugu Matsukawa Taku Fujiwara 《Journal of Material Cycles and Waste Management》2016,18(4):608-617
Ash produced from the combustion of livestock manure contains large amounts of phosphorus (P), which is an important resource as a fertilizer. Some studies have extracted and recovered P from incinerated biomass ash using inorganic acid or alkaline agents, which produce wastewater that requires treatment and is expensive due to the cost of chemicals. Livestock manure ash contains not only P, but also water soluble salts, which could be a negative influence on plant growth and shall be preferably removed from the recovered fertilizer. In this study, we removed salinity from cattle manure incineration ash by simple aqueous leaching, while retaining the P content. The optimal condition was a 20 min leaching time at a liquid/solid (L/S) ratio of 10 mL g-ash?1. Under this condition, over 90 % of Cl and 20 % of Na in the original ash was removed, while over 99 % of the P was retained in the leached residue. The leached residue met the fertilizer standard in Japan in terms of citrate soluble fertilizer components and contained few heavy metals. X-ray analyses of the ash indicated that Cl was mainly present as KCl in the original ash, while P was mainly present as Ca compounds in the ash. 相似文献
970.
Oscar Valerio Manjusri Misra Amar K. Mohanty 《Journal of Polymers and the Environment》2018,26(3):1078-1087
Poly(butylene succinate) (PBS) was melt blended with glycerol based polyesters (PGS) synthesized from pure and technical glycerol aiming to improve the impact strength of PBS. It was found that after addition of 30 wt% PGS to PBS its impact strength was significantly increased by 344% (from 31.9 to 110 J/m) and its elongation at break was maintained at 220%. Infrared spectra of the blends showed the presence of hydroxyl groups from the PGS phase suggesting that hydrogen bonding between the phases could be responsible for a good stress transfer and an efficient toughening in the PBS/PGS blends. Scanning electron microscopy imaging showed a good dispersion of PGS phase into PBS with a PGS particle size of 10 μm and less and no agglomeration. Addition of PGS to PBS was shown to be an effective strategy for improvement of PBS impact resistance without serious detrimental effects on its thermal and rheological properties. 相似文献