全文获取类型
收费全文 | 510篇 |
免费 | 15篇 |
国内免费 | 21篇 |
专业分类
安全科学 | 80篇 |
废物处理 | 22篇 |
环保管理 | 79篇 |
综合类 | 136篇 |
基础理论 | 145篇 |
环境理论 | 7篇 |
污染及防治 | 28篇 |
评价与监测 | 4篇 |
社会与环境 | 42篇 |
灾害及防治 | 3篇 |
出版年
2024年 | 1篇 |
2023年 | 12篇 |
2022年 | 9篇 |
2021年 | 19篇 |
2020年 | 24篇 |
2019年 | 18篇 |
2018年 | 17篇 |
2017年 | 42篇 |
2016年 | 44篇 |
2015年 | 34篇 |
2014年 | 46篇 |
2013年 | 93篇 |
2012年 | 5篇 |
2011年 | 13篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 10篇 |
2007年 | 13篇 |
2006年 | 15篇 |
2005年 | 16篇 |
2004年 | 16篇 |
2003年 | 14篇 |
2002年 | 15篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1992年 | 1篇 |
1989年 | 4篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有546条查询结果,搜索用时 93 毫秒
401.
402.
Strategic Environmental Assessment of Plans and Programs: A Methodology for Estimating Effects on Biodiversity 总被引:1,自引:0,他引:1
We developed a methodology for biodiversity evaluations within the process of Strategic Environmental Assessment and we applied
it to the estimation of the effect of two Regional Plans of Development on all bird species inhabiting the Castilla y León
region (northwestern Spain). The methodology is based on the evaluation of the effects of main development actions on the
habitat requirements of species. From these evaluations, and from data on the current distribution and population size (number
of individuals) of each species, we estimated the most likely pattern of distribution and population size after the full implementation
of the plans for each species. The impacts of the plans were quantified as the differences between the pre- and postproject
patterns after codifying them to compensate for differences in the quality of the information available among species. Overall,
we conclude that the proposed methodology fulfills the requirements for its use within the SEA process as it allows for the
assessment of cumulative impacts on every species, highlighting the development directions and the habitat types with major
impacts, and ascertaining whether impacts affect species with either low or high conservation and/or economic value. Generalization
of the proposed methodology to other regions or species will require wildlife-habitat models adequate for SEA analyses, so
that we also propose guidelines for the development and validation of these models. 相似文献
403.
Michael A. Collins 《Journal of the American Water Resources Association》1972,8(6):1253-1258
Steady state experimental studies with a viscous analog of the aquifer system in central Long Island, New York, have shown there to be significant interaction between surface accretion, stream base flow, well recharge, and the degree of salt water intrusion. Reductions in accretion are found to cause a proportionately larger decrease in stream base flow. The degree of intrusion is found to be related to the distribution of accretion and well recharge between stream base flow and submarine flow to the sea. This interaction poses a conflict between development of the groundwater resource and maintenance of the surface water resource. Well recharge apparently offers a potential solution to the conflict. 相似文献
404.
Md Nazmul Azim Beg Ehab A. Meselhe Dong Ha Kim James Halgren Adam Wlostowski Fred L. Ogden Trey Flowers 《Journal of the American Water Resources Association》2023,59(2):257-280
Operational forecast models require robust, computationally efficient, and reliable algorithms. We desire accurate forecasts within the limits of the uncertainties in channel geometry and roughness because the output from these algorithms leads to flood warnings and a variety of water management decisions. The current operational Water Model uses the Muskingum-Cunge method, which does not account for key hydraulic conditions such as flow hysteresis and backwater effects, limiting its ability in situations with pronounced backwater effects. This situation most commonly occurs in low-gradient rivers, near confluences and channel constrictions, coastal regions where the combined actions of tides, storm surges, and wind can cause adverse flow. These situations necessitate a more rigorous flow routing approach such as dynamic or diffusive wave approximation to simulate flow hydraulics accurately. Avoiding the dynamic wave routing due to its extreme computational cost, this work presents two diffusive wave approaches to simulate flow routing in a complex river network. This study reports a comparison of two different diffusive wave models that both use a finite difference solution solved using an implicit Crank–Nicolson (CN) scheme with second-order accuracy in both time and space. The first model applies the CN scheme over three spatial nodes and is referred to as Crank–Nicolson over Space (CNS). The second model uses the CN scheme over three temporal nodes and is referred to as Crank–Nicolson over Time (CNT). Both models can properly account for complex cross-section geometry and variable computational points spacing along the channel length. The models were tested in different watersheds representing a mixture of steep and flat topographies. Comparing model outputs against observations of discharges and water levels indicated that the models accurately predict the peak discharge, peak water level, and flooding duration. Both models are accurate and computationally stable over a broad range of hydraulic regimes. The CNS model is dependent on the Courant criteria, making it less computational efficient where short channel segments are present. The CNT model does not suffer from that constraint and is, thus, highly computationally efficient and could be more useful for operational forecast models. 相似文献
405.
Dechun Jiang Xumao Zhao Jordi López-Pujol Zhiqiang Wang Yanhua Qu Yanming Zhang Tongzuo Zhang Dayong Li Ke Jiang Bin Wang Chaochao Yan Jia-Tang Li 《Conservation biology》2023,37(4):e14069
Over the past 40 years, the climate has been changing and human disturbance has increased in the vast Qinghai–Tibet Plateau (QTP). These 2 factors are expected to affect the distribution of a large number of endemic vertebrate species. However, quantitative relationships between range shifts and climate change and human disturbance of these species in the QTP have rarely been evaluated. We used occurrence records of 19 terrestrial vertebrate species (birds, mammals, amphibians, and reptiles) occurring in the QTP from 1980 to 2020 to quantify the effects of climate change and anthropogenic impacts on the distribution of these 4 taxonomic groups and estimated species range changes in each species. The trend in distribution changes differed among the taxonomic groups, although, generally, ranges shifted to central QTP. Climate change contributed more to range variation than human disturbance (the sum of the 4 climatic variables contributed more than the sum of the 4 human disturbance variables for all 4 taxonomic groups). Suitable geographic range increased for most mammals, amphibians, and reptiles (+27.6%, +18.4%, and +27.8% on average, respectively), whereas for birds range decreased on average by 0.9%. Quantitative evidence for climate change and human disturbance associations with range changes for endemic vertebrate species in the QTP can provide useful insights into biodiversity conservation under changing environments. 相似文献
406.
João L. Guilherme Victoria R. Jones Inês Catry Martin Beal Maria P. Dias Steffen Oppel Juliet A. Vickery Chris M. Hewson Stuart H. M. Butchart Ana S. L. Rodrigues 《Conservation biology》2023,37(1):e14002
The conservation of long-distance migratory birds requires coordination between the multiple countries connected by the movements of these species. The recent expansion of tracking studies is shedding new light on these movements, but much of this information is fragmented and inaccessible to conservation practitioners and policy makers. We synthesized current knowledge on the connectivity established between countries by landbirds and raptors migrating along the African–Eurasian flyway. We reviewed tracking studies to compile migration records for 1229 individual birds, from which we derived 544 migratory links, each link corresponding to a species’ connection between a breeding country in Europe and a nonbreeding country in sub-Saharan Africa. We used these migratory links to analyze trends in knowledge over time and spatial patterns of connectivity per country (across species), per species (across countries), and at the flyway scale (across all countries and all species). The number of tracking studies available increased steadily since 2010 (particularly for landbirds), but the coverage of existing tracking data was highly incomplete. An average of 7.5% of migratory landbird species and 14.6% of raptor species were tracked per country. More data existed from central and western European countries, and it was biased toward larger bodied species. We provide species- and country-level syntheses of the migratory links we identified from the reviewed studies, involving 123 populations of 43 species, migrating between 28 European and 43 African countries. Several countries (e.g., Spain, Poland, Ethiopia, Democratic Republic of Congo) are strategic priorities for future tracking studies to complement existing data, particularly on landbirds. Despite the limitations in existing tracking data, our data and results can inform discussions under 2 key policy instruments at the flyway scale: the African–Eurasian Migratory Landbirds Action Plan and the Memorandum of Understanding on the Conservation of Migratory Birds of Prey in Africa and Eurasia. 相似文献
407.
Analysis of variations in water–soluble organic matter (WSOM) δ13C of leaves and phloem can efficiently describe the δ13C distributions within plants and identify the temporal variation of δ13C. In this study, WSOM δ13C values of both leaves and phloem (twig, stem, and root) of Platycladus orientalis were measured during seven sunny days, including 2–hour interval measurements at three days for diel pattern analysis and 6–hour interval measurements at the remaining four days for day–to–day variation analysis. Analysis of WSOM δ13C in different plant organs showed that 13C was generally depleted from leaves to twigs, then enriched in stems and subsequently depleted in roots. Stems were significantly 13C–enriched compared to twigs (p?<?0.05), while δ13C differences between stems and other organs and among leaves, twigs and roots were not significant (p?>?0.05). No clear diel patterns in δ13C of leaves and phloem were found. Daily average δ13C values indicated that all plant organs had more positive values on sunny days during the dry season than during the wet season. Both photosynthetic and post–photosynthetic fractionation influence variations in WSOM δ13C. These results have implications for research on plant physiology and plant water use. 相似文献
408.
Insulation is typically used in extra-large double-walled cryogenic storage tanks that are used to store liquid natural gas (LNG). These vessels have been designed with the assumption that the insulation offers negligible structural resistance that might cause structural damage. Observation of the deformation of the insulation in such tanks leads to concern that the insulation may become sufficiently compacted to cause significant load transfer between the inner and outer tank. The inner tank, though protected from most external events by the outer tank, is only designed to contain the liquid gas. It is therefore much more sensitive to seismic effects. In this investigation, simplified and 3D finite element models are used to simulate the interaction effects of the fluid, inner tank, insulation and outer tank. This paper presents an initial analysis of the potential effects of LNG tank insulation under earthquake conditions and assesses the potential for structural damage by comparison of models that do or do not consider the insulation layer. The data reported and statistically sorted include the overturning moment, the base shear, the tank wall stress, and the wave height in the tank. The results show that the insulation layer has certain influence on seismic design of LNG tanks. 相似文献
409.
《Process Safety and Environmental Protection》2014,92(5):406-411
Management of a plant alarm system has been identified as one of the key safety issues because of disasters caused by alarm floods. When a chemical plant is at abnormal state, an alarm system must provide useful information to operators as the third layer of an independent protection layer (IPL). Therefore, a method of designing a plant alarm system is important for plant safety. Because the plant is maintained in the plant lifecycle, the alarm system for the plant should be properly managed through the plant lifecycle. To manage changes, the design rationales of the alarm system should be explained explicitly. This paper investigates a logical and systematic alarm system design method that explicitly explains the design rationales from know-why information for proper management of changes through the plant lifecycle. In the method, the module structure proposed by Hamaguchi et al. (2011) to assign a fault origin to be distinguished is extended. Using modules to investigate the sets of alarm sensors and the alarm limits setting for first alarm alternative signals to distinguish the fault origin, an alarm system design method is proposed. Also, the completeness of fault propagation for a branch of the cause–effect model as the plant model is explained. Using the modules and the set of fault origins to be distinguished by the alarm system, we try to explicitly explain the design rationales of the alarm system. 相似文献
410.
《Process Safety and Environmental Protection》2014,92(6):888-895
The three layer artificial neural network model was applied to predict the degradation efficiency for carbamazepine in photocatalytic oxidation under UV radiation. Titania–zirconia was employed as a catalyst for the photooxidation. The catalyst was prepared using titanium isopropoxide and zirconium oxychloride by sol–gel method and characterized by transmission electron microscopy and BET analysis. Different process parameters such as, initial concentration of carbamazepine, pH of the solution, catalyst concentration and time of UV irradiation were employed as the input to the artificial neural network model and the output of the network was degradation efficiency of carbamazepine. The multilayer feed-forward networks with the Levenberg–Marquardt (trainlm) backpropagation training algorithm was used for the network training. The smallest mean square error was obtained for three-layer network with ‘logsig’ transfer function and five neurons in the hidden layer gave optimal results. A comparison between the predicted values and selective experimental data of degradation efficiency showed a high correlation coefficient (R2) of 0.997. 相似文献