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61.
This paper assesses the long term impacts of an international transfer called the Reduced Emissions from Deforestation and Degradation (REDD) mechanism, which aims at preserving tropical forests of the recipient economy. This two-sector economy faces a dilemma between economic growth and deforestation. The rural sector can substitute reproducible capital for agricultural land whereas the manufacturing sector only requires capital. The model shows that the REDD mechanism has a non-monotonic effect on steady state welfares. For low transfer schemes, the agricultural output increases with the transfer even though less land is under cultivation. For high transfer schemes, the increase in the transfer may not offset the decrease in the agricultural output. The open-loop symmetric Nash equilibrium in a dynamic deforestation game predicts that redistributing the transfer among a finite number of producers is less efficient in reducing deforestation than in the social optimum.  相似文献   
62.
To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in sediments from the Bizerte Lagoon (northern Tunisia), 18 surface sediment samples were collected in March 2011 and analyzed for 14 US Environmental Protection Agency priority PAHs by high-performance liquid chromatography. The total concentrations of the 14 PAHs (ΣPAHs) ranged from 16.9 to 394.1 ng g?1 dry weight (dw) with a mean concentration of 85.5 ng g?1 dw. Compared with other lagoons, coasts, and bays in the world, the concentrations of PAHs in surface sediments of the Bizerte Lagoon are low to moderate. The PAHs’ composition pattern was dominated by the presence of four-ring PAHs (45.8 %) followed by five-ring (26.8 %) and three-ring PAHs (12.7 %). The PAH source analysis suggested that the main origin of PAHs in the sediments of the lagoon was mainly from pyrolytic sources. According to the numerical effect-based sediment quality guidelines of the USA, the levels of PAHs in the Bizerte Lagoon should not exert adverse biological effects. The total benzo[a]pyrene toxicity equivalent values calculated for the samples varied from 3.1 to 53.7 ng g?1 dw with an average of 10.6 ng g?1 dw.  相似文献   
63.
Soil contamination by metals engenders important environmental and health problems in northern France where a smelter (Metaleurop Nord) was in activity for more than a century. This study aims to look at the long-term effects of the smelter after its closedown by combining data on the degree of soil contamination and the quality of the crops grown (agricultural crops and homegrown vegetables) in these soils for a better assessment of the local population’s exposure to Cd, Pb, and Zn. Seven years after the Metaleurop Nord closedown, (1) the agricultural and urban topsoils were strongly contaminated by Cd, Pb, and Zn; (2) the kitchen garden topsoils were even more polluted than the agricultural soils, with great variability in metal concentrations within the gardens studied; (3) a high proportion of the agricultural crops for foodstuffs did not conform with the European legislation; (4) for feedstuffs, most samples did not exceed the Cd and Pb legislation limits, indicating that feedstuffs may be an opportunity for most agricultural produce; and (5) a high proportion of the vegetables produced in the kitchen gardens did not conform with the European foodstuff legislation. The high contamination level of the soils studied continues to be a risk for the environment and the population’s health. A further investigation (part 2) assesses the associated potential health risk for local inhabitants through consumption of homegrown vegetables and ingestion of soil particles by estimating the site-specific human health assessment criteria for Cd and Pb.  相似文献   
64.
Alien plant invasions contribute significantly to global changes by often affecting biodiversity and ecosystem processes. Operational methods for identifying landscape attributes that promote or constrain plant invasions are urgently needed to predict their future spread and manage them efficiently. We combined landscape and functional ecology concepts to define patch mosaic functional types (PMFTs) as groups of cells showing the same response to a plant invasion in a heterogeneous forest landscape. The invasion of a European temperate forest by the American black cherry (Prunus serotina) has been chosen as a case study. A set of variables was collected, mapped using a Geographic Information System, and analyzed with multivariate analyses to correlate landscape traits with Prunus serotina abundance in each cell of a grid overlaid on the forest. A risk index was derived and mapped for three invasion levels: seedling colonization, tree establishment, and ecosystem invasion. Five PMFTs were identified and characterized by a set of traits related to soil properties, land use, disturbance, and invasion history. Scots pine plantations on podzols were the most invasible, while cells dominated by hydromorphic or calcareous soils were the most resistant. Most colonized patch mosaics provided suitable conditions for future establishment and invasion. Being strongly spatially connected, suitable patches provide corridors for Prunus serotina to colonize new parts of the forest. Conversely, the most resistant PMFTs were spatially agglomerated in the south of the forest and could act as a barrier. Colonization, establishment, and invasion risk maps were finally obtained by combining partial risks associated with each landscape trait at the cell scale. Within a heterogeneous landscape, we defined and organized PMFTs into a hierarchy, according to their associated risk for colonization, establishment, or invasion by a given invasive species. Each hierarchical level should be associated with a management strategy aiming at reducing one or more partial risk. Monitoring safe areas, extending cutting rotations, harvesting recently colonized stands tree by tree, promoting a multilayered understory vegetation, cutting down reproducing alien trees, favoring shade-tolerant, fast-growing, native tree species, removing alien trees at the leading edge, and proposing soil enrichment or irrigation in heavily invaded areas are recommended.  相似文献   
65.
Journal of Material Cycles and Waste Management - For the first time in the world, raw tea waste from tea plants was mineralized by rapid biotechnological methods using beneficial worms, enzymes...  相似文献   
66.
Call rate can be a salient feature in animal communication. Depending on the species, different psychological variables appear to influence call rates but the exact nature of these relationships remains poorly explored. Here, we demonstrate for free-ranging Campbell’s monkeys that the call rates of four different alarm series (termed H, K, K+, and B series) vary systematically as a function of context, associated behaviour, and identity of the caller. K+ series were given more rapidly to predation than non-predation events, K+ and K series more rapidly to visual than auditory predator detection, and H series more rapidly while counterattacking an eagle than staying put. Finally, there were individual differences in B series, suggesting that call rate potentially provides listeners with cues about the caller’s anti-predator behaviour, event type experienced, and his identity.  相似文献   
67.
The increased popularity of bridge employment has raised questions about its consequences for well‐being in late adult life. This research explored the consequences of bridge employment for the level of life satisfaction of older adults during the retirement transition period. Changes in life satisfaction were considered to be a function of the different intentions and motives for taking bridge jobs. Furthermore, the impact of bridge employment was empirically examined conditional on the voluntariness of the exit from the career job. Panel data on Dutch retirees (N = 1248) were investigated using conditional change models. The results demonstrate that older adults willing to prolong their work careers but unable to find bridge jobs reported lower levels of life satisfaction compared with full retirees not considering bridge employment. In addition, participation in bridge employment for financial motives was associated with decreases in life satisfaction compared with postretirement working based on intrinsic motives. Moreover, compared with voluntary retirement, involuntary retirement was detrimental to life satisfaction, but participation in a bridge job was found to mitigate this negative shock. These findings contribute to the understanding of the consequences of various postretirement employment trajectories for older individuals. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
68.
This study was aimed at assessing the levels of 210Pb and 210Po concentrations as well as gross alpha and beta activities in environmental monitors from the Catalan stretch of the Ebro River (Spain), potentially influenced by the presence of sediments with high concentrations of 238U and its decay chain daughters in the Flix reservoir. The chronic daily intake of 210Pb and 210Po through ingestion and inhalation of soils was evaluated, and the derived non-carcinogenic and carcinogenic risks were characterized. The low concentration of radioisotopes in soils resulted in a negligible annual effective dose. The levels of 210Pb and 210Po were determined in various groups of highly consumed food (fish and seafood, vegetables, fruits, and rice), and their dietary intake was calculated. The annual effective dose for the adult people from food intake was estimated in 3.3 × 10???2 mSv, mostly due to 210Po. Overall, the current radioactivity levels in the Catalan stretch of the Ebro River should not mean any additional health risk for the population living nearby. However, an integral assessment of the risks derived from exposure to other pollutants (e.g., metals and organochlorine compounds) jointly with radionuclides could be of great interest.  相似文献   
69.
This paper examines the challenge of achieving a balance between the implementation of centrally designed pro-poor policies and the decentralization of responsibilities to local governments in many African countries. It analyzes the implementation of the Rural Water Supply and Sanitation Program in Tanzania. Key mechanisms for planning and allocating resources are analyzed at ministry, district, and village levels. Results show that a mixture of policy incoherencies, technical shortcomings and political influence determine that only a small proportion of funds reaches the underserved areas. We argue that a greater connection between the bottom-up and top-down planning mechanisms, and a sharp increase of downwards accountability are needed before decentralized decision-making result in better resources allocation. Meanwhile a bigger intervention from central government is needed.  相似文献   
70.
Trisomy of the short arm of chromosome 4 is a well-known syndrome, and several observations have been made in the last 30 years. Herein, we report a new observation of trisomy 4p in a fetus with a semi-lobar holoprosencephaly (HPE), dysmorphic features and multiple malformations. The diagnosis of HPE was made, at 33 weeks' gestation, on the fetus of a healthy G1P0 woman. Amniocentesis was performed for chromosome analysis and additional material was found on a chromosome 22. The couple elected to terminate the pregnancy and fetal examination was realized. Conventional and molecular cytogenetic studies were performed on the fetus and the parents, which showed that the additional material found on one chromosome 22 corresponded to the short arm of chromosome 4 and therefore led us to establish a diagnosis of trisomy 4p inherited from the malsegregation of a paternal translocation t(4;22)(q12;q11.1). The etiology of HPE is very heterogeneous; it includes non-genetic factors such as maternal diabetes and genetic causes. HPE cases have been described in association with many chromosomal anomalies, trisomy 13 being the most frequent. However, to our knowledge, HPE has never been previously reported in association with a trisomy involving solely the short arm of chromosome 4. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
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