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431.
Correctly quantifying the impacts of rare apex marine predators is essential to ecosystem-based approaches to fisheries management, where harvesting must be sustainable for targeted species and their dependent predators. This requires modelling the uncertainty in such processes as predator life history, seasonal abundance and movement, size-based predation, energetic requirements, and prey vulnerability. We combined these uncertainties to evaluate the predatory impact of transient leopard seals on a community of mesopredators (seals and penguins) and their prey at South Georgia, and assess the implications for an ecosystem-based management. The mesopredators are highly dependent on Antarctic krill and icefish, which are targeted by regional fisheries. We used a state-space formulation to combine (1) a mark-recapture open-population model and individual identification data to assess seasonally variable leopard seal arrival and departure dates, numbers, and residency times; (2) a size-based bioenergetic model; and (3) a size-based prey choice model from a diet analysis. Our models indicated that prey choice and consumption reflected seasonal changes in leopard seal population size and structure, size-selective predation and prey vulnerability. A population of 104 (90–125) leopard seals, of which 64% were juveniles, consumed less than 2% of the Antarctic fur seal pup production of the area (50% of total ingested energy, IE), but ca. 12–16% of the local gentoo penguin population (20% IE). Antarctic krill (28% IE) were the only observed food of leopard seal pups and supplemented the diet of older individuals. Direct impacts on krill and fish were negligible, but the “escapement” due to leopard seal predation on fur seal pups and penguins could be significant for the mackerel icefish fishery at South Georgia. These results suggest that: (1) rare apex predators like leopard seals may control, and may depend on, populations of mesopredators dependent on prey species targeted by fisheries; and (2) predatory impacts and community control may vary throughout the predator's geographic range, and differ across ecosystems and management areas, depending on the seasonal abundance of the prey and the predator's dispersal movements. This understanding is important to integrate the predator needs as natural mortality of its prey in models to set prey catch limits for fisheries. Reliable estimates of the variability of these needs are essential for a precautionary interpretation in the context of an ecosystem-based management. 相似文献
432.
Marzena Ucherek 《国际发展与全球生态学杂志》2013,20(1):63-67
Current trends in the development of the world packaging market and the place of ecological tendencies in them suggest the need to analyse the present status of studies on the ecological assessment of packaging materials and packaging. The aim of this study is to present some aspects of ecological assessment of packaging. The methods and criteria of ecological assessment of packaging, including Life Cycle Analysis (LCA) and ecological classification of packaging proposed by COBRO (Polish Packaging Research and Development Centre) in Warsaw were used. The considerations presented in the paper related to the general assumptions of ecological assessment of packaging materials and packaging point to the complexity of the problem and, at the same time, to the immediate interest and importance of studies in this field, particularly in terms of implementing a specific environmental protection policy. 相似文献
433.
我国塑料包装废物的产生和回收特性及管理对策 总被引:5,自引:2,他引:3
通过现场调查和资料调研,分析了塑料包装废物的流向和环境特征,总结了塑料包装废物回收的基本特点和经验教训,论述了塑料包装废物回收模式特点,深入分析了回收过程中存在的问题,并提出了加强塑料包装废物回收的管理对策. 结果表明:塑料包装是塑料制品中的重要构成部分,由于质量轻、回收体积大,不易回收,我国每年产生大量的塑料包装废物,城市生活垃圾填埋场成为塑料包装废物的主要流向和污染源. 目前我国塑料包装废物回收依托的是进城务工的个体回收者,与现阶段的国情相符合. 塑料污染问题不是短期内能解决的,必须采取长期的综合管理对策,如进行源头减量化、制定鼓励回收利用的经济政策、采取适宜的无害化处置方式等. 相似文献
434.
We studied the effects of winter water drawdowns (2.3 m) on beavers in Voyageurs National Park, Minnesota, USA. Our study
was designed to sample areas within the park that differed in water drawdown regime. Lodges were counted and beavers were
livetrapped and radio-implanted to study behavior, movements, and mortality. Active beaver lodge density, determined by aerial
survey in 1984 and 1986, was greatest along the shoreline of the drawdown reservoir. In winter beavers living on the drawdown
reservoir spent less time inside their lodges than did beavers from stable water environments, foraged more above ice, and
they were unable to fully use stored food. Only one case of starvation in the drawdown reservoir was documented, but beavers
in reservoirs that were drawn down survived winter in poorer condition than did beavers living in areas in which water levels
remained high. In spite of an increasing population and lack of widespread mortality, winter water drawdowns did alter beaver
behavior. To reduce these impacts, total annual water fluctuation should not exceed 1.5 m, and winter drawdown should not
exceed 0.7 m. Possible management alternatives and costs are discussed. 相似文献
435.
Eckerman DA Abrahamson K Ammerman T Fercho H Rohlman DS Anger WK 《Journal of Safety Research》2004,35(3):317-327
INTRODUCTION: Interactive computer-based safety instruction (CBI) was given to 73 workers in the food services department of an urban hospital. RESULTS: Post-test accuracy (95%) improved significantly (p < or = 0.0001) from the pre-test (74.5 %), d = 1.09. Generalization was confirmed by increased accuracy in answering questions, posed on-the-job, that required application of knowledge to the work setting (from 46% to 79%; p < 0.0001). Problematic kitchen conditions such as puddles increased slightly after training, but adjustment for increasing production/workload revealed an overall post-training decline in problems from 0.58 to 0.32 (p = 0.0001, d = 0.89). Work practice improvement was seen in 79% of workers (p < 0.0001, d = 1.00). Effect sizes (d) of knowledge, location, and work practice improvements are large and demonstrate that the benefits of CBI extend to the workplace floor. Further, the decrease between knowledge and behavior change (d = 0.09-0.2) is less than reported following other forms of training. 相似文献
436.
V.?Krishna?PrasadEmail author Ben?Stinner Deb?Stinner John?Cardina Richard?Moore Prabhat?K.?Gupta Harao?Tsuruta Kiyoto?Tanabe K.?V.?S.?Badarinath Casey?Hoy 《Regional Environmental Change》2003,3(4):154-161
We studied trends in food production and nitrous oxide emissions from India's agricultural sector between 1961 and 2000. Data
from Food and Agricultural Statistics (FAO) have been gathered covering production, consumption, fertilizer use and livestock
details. IPCC 1996 revised guidelines were followed in studying the variations in N2O-N emissions. Results suggest that total N2O-N emissions (direct, animal waste and indirect sources) increased ~6.1 times from ~0.048 to ~0.294 Tg N2O-N, over 40 years. Source-wise breakdown of emissions from 1961–2000 indicated that during 1961 most of the N2O-N inputs were from crop residues (61%) and biological nitrogen fixation (25%), while during 2000 the main sources were synthetic
fertilizer (~48%) and crop residues (19%). Direct emissions increased from ~0.031 to ~0.183 Tg. It is estimated that ~3.1%
of global N2O-N emissions comes from India. Trends in food production, primarily cereals (rice, wheat and coarse grains) and pulses, and
fertilizer consumption from 1961–2000 suggest that food production (cereals and pulses) increased only 3.7 times, while nitrogenous
fertilizer consumption increased ~43 times over this period, leading to extensive release of nitrogen to the atmosphere. From
this study, we infer that the challenge for Indian agriculture lies not only in increasing production but also in achieving
production stability while minimizing the impact to the environment, through various management and mitigation options. 相似文献
437.
Jeremy Shoham 《Disasters》1987,11(4):282-285
A major area of investment in data collection in developing countries has been that of nutritional surveillance and monitoring. From recent debate it is clear that there is currently no consensus on the potential role of nutritional status as an early warning indicator. The author presents a synthesis of the broad spectrum of views on the role nutritional surveillance could or should have in early warning. Conceptual problems and technical difficulties are reviewed in the light of recent experiences in Africa and Asia. The author raises a number of issues for future discussion in this ongoing debate. 相似文献
438.
Sally Dunbar 《Disasters》1984,8(3):174-177
In a long term Somali refugee camp where nutritional and general health status of children is now considered satisfactory and stable, a randomized community based survey of 300 children under five years was undertaken. Results indicate that the prevalence of protein-energy malnutrition is rising again: 17.3% of children are <80% median weight/height and 1.7% are <70%median weight/height. In addition, there is a high prevalence of anaemia: 50.5% have a haemoglobin level <9g% and 10.8%≤6g%. This cannot be explained by chronic malaria as the spleen rate is only 2%. Stool examination of 161 children show 29.8% to have evidence of Giardia Lamblia infection but this is not statistically correlated with either anaemia or with protein-energy malnutrition. Other potentially pathogenic parasites are uncommon and no hookworm is seen. Examination of blood films of anaemic children shows hypochromia as a striking feature.
It is concluded that nutritional deficiencies are a likely major factor in the aetiology of the anaemia. Both protein-energy malnutrition and anaemia seem related to the weaning period. Food rations for refugees, although adequate for short term needs, may be qualitatively deficient for long term subsistence, especially as regards young children. 相似文献
It is concluded that nutritional deficiencies are a likely major factor in the aetiology of the anaemia. Both protein-energy malnutrition and anaemia seem related to the weaning period. Food rations for refugees, although adequate for short term needs, may be qualitatively deficient for long term subsistence, especially as regards young children. 相似文献
439.
440.
Munang Tingem Mike Rivington 《Mitigation and Adaptation Strategies for Global Change》2009,14(2):153-168
The Cameroonian agricultural sector, a critical part of the local ecosystem, is potentially vulnerable to climate change raising
concerns about food security in the country’s future. Adaptations policies may be able to mitigate some of this vulnerability.
This article investigates and addresses the issue of selected adaptation options within the context of Cameroonian food production.
A methodology is applied where transient diagnostics of two atmosphere–ocean general circulation models, the NASA/Goddard
Institute GISS and the British HadCM3, are coupled to a cropping system simulation model (CropSyst) to simulate current and
future (2020, 2080) crop yields for selected key crops (bambara nut, groundnut, maize, sorghum, and soybean) in eight agricultural
regions of Cameroon. Our results show that for the future, substantial yield increases are estimated for bambara groundnut,
soybean and groundnut, while little or no change or even decreases for maize and sorghum yields, varying according to the
climate scenario and the agricultural region investigated. Taking the “no regrets” principle into consideration, we explore
the advantages of specific adaptation strategies specifically for three crops viz. maize, sorghum and bambara groundnut, under
GISS A2 and B2 marker scenarios only. Changing sowing dates may be ineffective in counteracting adverse climatic effects because
of the narrow rainfall band that strictly determines the timing of farm operations in Cameroon. In contrast, the possibility
of developing later maturing new cultivars proved to be extremely effective in offsetting adverse impacts, giving the highest
increases in productivity under different scenario projections without management changes. For example, under climate change
scenario GISS A2 2080, a 14.6% reduction in maize yield was converted to a 32.1% increase; a 39.9% decrease in sorghum yield
was converted to a 17.6% increase, and for bambara groundnut (an under-researched and underutilised African legume), yields
were almost trebled (37.1% increase above that for sowing date alone (12.9%)) due to increase length of growing period and
the positive effects of higher CO2 concentrations. These results may better inform wider studies and development strategies on sustainable agriculture in the
area by providing an indication as to the potential direction in shifts in production capabilities. Our approach highlights
the benefit of using models as tools to investigate potential climate change impacts, where results can supplement existing
knowledge. The results provide useful guidance and motivation to public authorities and development agencies interested in
food security issues in Cameroon and elsewhere. 相似文献