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621.
Outdoor versus indoor contributions to indoor particulate matter (PM) determined by mass balance methods 总被引:2,自引:0,他引:2
Kopperud RJ Ferro AR Hildemann LM 《Journal of the Air & Waste Management Association (1995)》2004,54(9):1188-1196
This study compares an indoor-outdoor air-exchange mass balance model (IO model) with a chemical mass balance (CMB) model. The models were used to determine the contribution of outdoor sources and indoor resuspension activities to indoor particulate matter (PM) concentrations. Simultaneous indoor and outdoor measurements of PM concentration, chemical composition, and air-exchange rate were made for five consecutive days at a single-family residence using particle counters, nephelometers, and filter samples of integrated PM with an aerodynamic diameter of less than or equal to 2.5 microm (PM2.5) and PM with an aerodynamic diameter of less than or equal to 5 microm (PM5). Chemical compositions were determined by inductively coupled plasma mass-spectrometry. During three high-activity days, prescribed activities, such as cleaning and walking, were conducted over a period of 4-6 hr. For the remaining two days, indoor activities were minimal. Indoor sources accounted for 60-89% of the PM2.5 and more than 90% of the PM5 for the high-activity days. For the minimal-activity days, indoor sources accounted for 27-47% of PM2.5 and 44-60% of the PM5. Good agreement was found between the two mass balance methods. Indoor PM2.5 originating outdoors averaged 53% of outdoor concentrations. 相似文献
622.
Peter A. Benn Andrea Gainey Charles J. Ingardia John F. Rodis James F. X. Egan 《黑龙江环境通报》2001,21(8):680-686
Second trimester maternal serum alpha-fetoprotein (MS-AFP), human chorionic gonadotrophin (hCG), unconjugated estiol (uE3), and inhibin-A (INH-A) levels were evaluated in pregnancies complicated by triploidy. In addition to seven new triploid pregnancies, the results for 67 published cases were reviewed. All cases appear to fall into two major groups. First, those identifiable as screen-positive for both Down syndrome and an open neural tube defect (ONTD) with elevated MS-AFP, grossly elevated hCG, low/normal uE3, and probably elevated INH-A. Pregnancies in the second group are identifiable as screen-positive for trisomy 18 with low/normal MS-AFP, and very low hCG, uE3 and INH-A. Triploid pregnancies with high maternal serum hCG nearly always show a placenta with partial mole (25/27 or 93%), a high frequency of ONTDs or ventral wall defects (VWDs) (8/28 or 29%) and have either an XXX or XXY karyotype (observed ratio 6:10, respectively). Low hCG is infrequently associated with a molar placenta (1/11 or 9%), does not appear to be associated with ONTDs or VWDs (0/29 or 0%), and shows an excess of XXX over XXY karyotypes (observed ratio 17:2). There were 16 cases with either a molar placenta, an ONTD or a VWD that received the MS-AFP and hCG tests. All 16 were screen-positive for an ONTD (MS-AFP≥2 multiples of the median). In addition, all 31 cases that received MS-AFP, hCG, uE3 (and where available INH-A) were screen-positive for either Down syndrome or trisomy 18. The findings are discussed in the context of expected differences between digynic and diandric triploidy. It is suggested that the sex chromosome complement in triploidy is an important factor in determining risk for partial mole development and in utero survival. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
623.
Isla Victoria (Nahuel Huapi National Park, Argentina), a large island dominated by native Nothofagus and Austrocedrus forest, has old plantations of many introduced tree species, some of which are famed invaders of native ecosystems elsewhere. There are also large populations of introduced deer and shrubs that may interact in a complex way with the introduced trees, as well as a recently arrived population of wild boar. Long-standing concern that the introduced trees will invade and transform native forest may be unwarranted, as there is little evidence of progressive invasion, even close to the plantations, despite over 50 years of opportunity. Introduced and native shrubs allow scattered introduced trees to achieve substantial size in abandoned pastures, but in almost all areas neither the trees nor the shrubs appear to be spreading beyond these sites. These shrub communities may be stable rather than successional, but the technology for restoring them to native forest is uncertain and probably currently impractical. Any attempt to remove the exotic tree seedlings and saplings from native forest would probably create the very conditions that would favor colonization by exotic plants rather than native trees, while simply clear-cutting the plantations would be unlikely to lead to regeneration of Nothofagus or Austrocedrus. The key to maintaining native forest is preventing catastrophic fire, as several introduced trees and shrubs would be favored over native dominant trees in recolonization. Deer undoubtedly interact with both native and introduced trees and shrubs, but their net effect on native forest is not yet clear, and specific management of deer beyond the current hunting by staff is unwarranted, at least if preventing tree invasion is the goal. The steep terrain and shallow soil make the recently arrived boar a grave threat to the native forest. Eradication is probably feasible and should be attempted quickly. 相似文献
624.
Michael Kwiatkowski Andrea L. Welker Robert G. Traver Megan Vanacore Tyler Ladd 《Journal of the American Water Resources Association》2007,43(5):1208-1222
Abstract: A pervious concrete infiltration basin was installed on the campus of Villanova University in August 2002. A study was undertaken to determine what contaminants, if any, were introduced to the soils underlying the site as a result of this best management practice (BMP). The average infiltration rate at the site is approximately 10?4 cm/s. The drainage area (5,208 m2) consists of grassy surfaces (36%), standard concrete/asphalt (30%), and roof surfaces (30%) that directly connect to the infiltration beds via downspouts and storm sewers. Composite samples of infiltrated stormwater were collected from the vadose zone using soil moisture suction devices. Discrete samples were collected from a port within an infiltration bed and a downspout from a roof surface. Samples from 17 storms were analyzed for pH, conductivity, and concentrations of suspended solids, dissolved solids, chloride, copper, and total nitrogen. Copper and chloride were the two constituents of concern at this site. Copper was introduced to the system from the roof, while chloride was introduced from deicing practices. Copper was not found in porewater beneath 0.3 m and the chloride was not significant enough to impact the ground water. This research indicates that with proper siting, an infiltration BMP will not adversely impact the ground water. 相似文献
625.
Rosa M. Pintó M. Isabel Costafreda Francisco J. Pérez-Rodriguez Lucía D’Andrea Albert Bosch 《Food and environmental virology》2010,2(3):127-135
Hepatitis A is the most common among all hepatitis worldwide in spite of an efficient vaccine and improved hygiene. Shellfish-borne
outbreaks are still of major concern causing hundreds of cases and huge economical losses in the present context of global
food trade. Hepatitis A virus (HAV) is a unique picornavirus with many differences in its molecular biology including both
its incapacity to induce the inhibition of the cellular protein synthesis and a highly biased and deoptimized codon usage
with respect the cell. The final goal of this intriguing strategy seems to be the need for a fine-tuning control of the translation
kinetics, particularly at the capsid coding region, and the underlying mechanism is the use of a right combination of common
and rare codons to allow a regulated ribosome traffic rate thus ensuring the proper protein folding. Capsid folding is critical
to warrant a high environmental stability for a virus transmitted through the fecal–oral route with long extracorporeal periods. 相似文献
626.
Andrea Cattaneo Ruben Lubowski Jonah Busch Anna Creed Bernardo Strassburg Frederick Boltz Ralph Ashton 《Environmental Science & Policy》2010,13(8):742-753
Reducing emissions from deforestation and forest degradation (REDD) can be an effective and efficient means of mitigating climate change. However, the perceived equity in the distribution of financial incentives for REDD could also emerge as a critical issue in international negotiations. The design of reference levels, which provide the benchmark for crediting emissions reductions, affects the economic incentives for national participation in a REDD mechanism and thus the overall willingness to reach an agreement on REDD. This paper compares the equity impacts of five proposed reference level designs using a partial-equilibrium model. Tradeoffs among equity, environmental effectiveness and cost-efficiency indicate the proposals trigger similar aggregate emissions reductions but lead to different outcomes in efficiency and alternative measures of equity. If equity across countries is measured as the financial incentive provided relative to a country's forest carbon stock, then a REDD mechanism compensating a uniform share of at-risk carbon stocks is the most equitable. On the other hand, if equity is evaluated as the financial incentive relative to the opportunity costs of participating in REDD, then the most equitable approach would be compensating emissions reductions but withholding a part of the payments to compensate for carbon stocks, which also encourages broader country participation under our model. 相似文献
627.
Andrea Bigano Francesco Bosello Roberto Roson Richard S. J. Tol 《Mitigation and Adaptation Strategies for Global Change》2008,13(8):765-791
While climate change impacts on human life have well defined and different origins, the interactions among the diverse impacts
are not yet fully understood. Their final effects, however, especially those involving social-economic responses, are likely
to play an important role. This paper is one of the first attempts to disentangle and highlight the role of these interactions.
It focuses on the economic assessment of two specific climate change impacts: sea-level rise and changes in tourism flows.
By using a Computable General Equilibrium (CGE) model the two impacts categories are first analysed separately and then jointly.
Considered separately, in 2050, the forecasted 25 cm. of sea level rise imply a GDP loss ranging from (−) 0.1% in South East
Asia to almost no loss in Canada, while redistribution of tourism flows – which in terms of arrivals favours Western Europe,
Japan, Korea and Canada and penalises all the other world regions – triggers GDP losses ranging from (−) 0.5% in Small Island
States to (−) 0.0004% in Canada. GDP gainers are Australia, New Zealand, Western Europe, Middle East and South Asia. The impact
of sea level rise and tourism were simulated jointly and the results compared with those of the two disjoint simulations.
From a qualitative point of view, the joint effects are similar to the outcomes of the disjoint exercises; from a quantitative
perspective, however, impact interaction does play a significant role. In six cases out of 16 there is a detectable (higher
than 2% and peaking to 70%) difference between the sum of the outcomes in the disjoint simulation and the outcomes of the
joint simulations. Moreover, the relative contribution of each single impact category has been disentangled from the final
result. In the case under scrutiny, demand shocks induced by changes in tourism flows outweigh the supply-side shock induced
by the loss of coastal land.
相似文献
Francesco BoselloEmail: |
628.
629.
Serrani Dominique Ajmone-Marsan Franco Corti Giuseppe Cocco Stefania Cardelli Valeria Adamo Paola 《Environmental geochemistry and health》2022,44(10):3425-3449
Environmental Geochemistry and Health - Urban soils are often mixed with extraneous materials and show a high spatial variability that determine great differences from their agricultural or natural... 相似文献
630.
Delgado-Vargas Carlos Andrés Espinosa-Barrera Paula Andrea Villegas-Guzman Paola Martínez-Pachón Diana Moncayo-Lasso Alejandro 《Environmental science and pollution research international》2022,29(28):42275-42289
Environmental Science and Pollution Research - In this work, the use of natural organic wastes (orange and lemon peels) as sources of citric acid was evaluated along with the application of the... 相似文献