全文获取类型
收费全文 | 4914篇 |
免费 | 139篇 |
国内免费 | 62篇 |
专业分类
安全科学 | 270篇 |
废物处理 | 168篇 |
环保管理 | 1245篇 |
综合类 | 534篇 |
基础理论 | 1349篇 |
环境理论 | 8篇 |
污染及防治 | 997篇 |
评价与监测 | 317篇 |
社会与环境 | 172篇 |
灾害及防治 | 55篇 |
出版年
2023年 | 60篇 |
2022年 | 56篇 |
2021年 | 56篇 |
2020年 | 62篇 |
2019年 | 69篇 |
2018年 | 122篇 |
2017年 | 133篇 |
2016年 | 179篇 |
2015年 | 121篇 |
2014年 | 160篇 |
2013年 | 407篇 |
2012年 | 232篇 |
2011年 | 304篇 |
2010年 | 202篇 |
2009年 | 236篇 |
2008年 | 260篇 |
2007年 | 255篇 |
2006年 | 227篇 |
2005年 | 195篇 |
2004年 | 180篇 |
2003年 | 149篇 |
2002年 | 140篇 |
2001年 | 86篇 |
2000年 | 94篇 |
1999年 | 68篇 |
1998年 | 74篇 |
1997年 | 60篇 |
1996年 | 63篇 |
1995年 | 78篇 |
1994年 | 74篇 |
1993年 | 66篇 |
1992年 | 57篇 |
1991年 | 39篇 |
1990年 | 35篇 |
1989年 | 36篇 |
1988年 | 30篇 |
1987年 | 39篇 |
1986年 | 40篇 |
1985年 | 39篇 |
1984年 | 44篇 |
1983年 | 44篇 |
1982年 | 52篇 |
1981年 | 43篇 |
1980年 | 31篇 |
1979年 | 15篇 |
1978年 | 29篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1972年 | 7篇 |
1971年 | 9篇 |
排序方式: 共有5115条查询结果,搜索用时 31 毫秒
261.
Research into national innovation systems (NISs) has received extensive academic and policy attention, and is especially relevant
with latecomer countries seeking to innovate in challenging industrial environments. In playing catch up with their early
industrializing counterparts, methods of learning take on increased importance in determining industrial success for latecomers.
The wind turbine technology innovation system is one that is highly dependent on both the extent of the national learning
processes and the strength of the national social-institutional setting. This research investigates the case of Taiwan, a
country which has embarked on a program to build its national innovative capacity in wind turbine technologies with specific
emphasis on Taiwan’s social sector. Within this system, the spotlight will be on four types of learning processes that interplay
during wind turbine development: learning by searching, learning by doing, learning by using, and learning by interacting. Through a case study of the emergence of Taiwan’s burgeoning large-scale wind power technology initiatives, the paper aims
to add to the understanding on how methods of learning impact upon the success of innovation systems. The findings show that
the industry’s future prospects are constrained because of the limited learning by interacting processes between turbine component producers, turbine owners, and researchers and because of weaknesses in the institutional
framework. This research also recognizes the importance that culture has on dominant forms of learning. 相似文献
262.
Sex-biased predation is thought to have important implications for sexual selection, sex allocation, and population dynamics (Magnhagen, 1991; Le-Galliard et al., 2005 for an example in lizards). Most studies found that males are subjected to higher predation pressure than females during the reproductive season (Korpimäki, 1985; Lodé et al., 2004; Christe et al., 2006; Costantini et al., 2007). In that period, males are very mobile, emit acoustic signals and exhibit brilliant colourations, which are needed to attract females but may make them more visible to predators. With regard to lizards, a recent study provided the first evidence that males of a lizard species may be preyed on more than females (Costantini et al., 2007). In the present study, we investigated whether there is sex-biased predation on two small lacertid species, the common wall lizard Podarcis muralis (Laurenti, 1768) and the Italian wall lizard Podarcis sicula (Rafinesque-Schmaltz, 1810), by Eurasian kestrels (Falco tinnunculus) during the reproductive season. We also examined whether (1) the rate of predation differed between species and (2) the rate of predation differed across years or among hunting habitats for each species. 相似文献
263.
The 2001 National Land Cover Database (NLCD) provides 30-m resolution estimates of percentage tree canopy and percentage impervious
cover for the conterminous United States. Previous estimates that compared NLCD tree canopy and impervious cover estimates
with photo-interpreted cover estimates within selected counties and places revealed that NLCD underestimates tree and impervious
cover. Based on these previous results, a wall-to-wall comprehensive national analysis was conducted to determine if and how
NLCD derived estimates of tree and impervious cover varies from photo-interpreted values across the conterminous United States.
Results of this analysis reveal that NLCD significantly underestimates tree cover in 64 of the 65 zones used to create the
NCLD cover maps, with a national average underestimation of 9.7% (standard error (SE) = 1.0%) and a maximum underestimation
of 28.4% in mapping zone 3. Impervious cover was also underestimated in 44 zones with an average underestimation of 1.4% (SE = 0.4%)
and a maximum underestimation of 5.7% in mapping zone 56. Understanding the degree of underestimation by mapping zone can
lead to better estimates of tree and impervious cover and a better understanding of the potential limitations associated with
NLCD cover estimates. 相似文献
264.
Nurul Leksmono Paul Dorfman Frank Burnet David Gibbs Emma Weitkamp 《Journal of Environmental Planning and Management》2010,53(5):559-571
Schedule 11 of the Environment Act 1995 underpins the requirement for consultation on air quality issues. The ongoing air quality review and assessment process represents one of the largest locally based science policy and communication initiatives ever undertaken in the UK. This paper outlines the practice of consultation and communication for Air Quality Management (AQM) and reviews the interaction between Environmental Health professionals, as the leading actor in the AQM process and other stakeholders involved in air quality consultation, including the public. Results are presented from a widespread questionnaire survey of English local authorities. Data indicate that the majority of air quality consultation has been carried out with statutory consultees (by sending the review and assessment reports) and the public (via websites and leaflets) in the form of information dissemination. 相似文献
265.
David G. Angeler Craig R. Allen Hannah E. Birgé Stina Drakare Brendan G. McKie Richard K. Johnson 《Ambio》2014,43(1):113-125
Freshwater ecosystems are important for global biodiversity and provide essential ecosystem services. There is consensus in the scientific literature that freshwater ecosystems are vulnerable to the impacts of environmental change, which may trigger irreversible regime shifts upon which biodiversity and ecosystem services may be lost. There are profound uncertainties regarding the management and assessment of the vulnerability of freshwater ecosystems to environmental change. Quantitative approaches are needed to reduce this uncertainty. We describe available statistical and modeling approaches along with case studies that demonstrate how resilience theory can be applied to aid decision-making in natural resources management. We highlight especially how long-term monitoring efforts combined with ecological theory can provide a novel nexus between ecological impact assessment and management, and the quantification of systemic vulnerability and thus the resilience of ecosystems to environmental change. 相似文献
266.
Christian Brandstätter David Laner Roman Prantl Johann Fellner 《Waste management (New York, N.Y.)》2014,34(12):2537-2547
Municipal solid waste landfills pose a threat on environment and human health, especially old landfills which lack facilities for collection and treatment of landfill gas and leachate. Consequently, missing information about emission flows prevent site-specific environmental risk assessments. To overcome this gap, the combination of waste sampling and analysis with statistical modeling is one option for estimating present and future emission potentials. Optimizing the tradeoff between investigation costs and reliable results requires knowledge about both: the number of samples to be taken and variables to be analyzed.This article aims to identify the optimized number of waste samples and variables in order to predict a larger set of variables. Therefore, we introduce a multivariate linear regression model and tested the applicability by usage of two case studies. Landfill A was used to set up and calibrate the model based on 50 waste samples and twelve variables. The calibrated model was applied to Landfill B including 36 waste samples and twelve variables with four predictor variables.The case study results are twofold: first, the reliable and accurate prediction of the twelve variables can be achieved with the knowledge of four predictor variables (Loi, EC, pH and Cl). For the second Landfill B, only ten full measurements would be needed for a reliable prediction of most response variables. The four predictor variables would exhibit comparably low analytical costs in comparison to the full set of measurements. This cost reduction could be used to increase the number of samples yielding an improved understanding of the spatial waste heterogeneity in landfills.Concluding, the future application of the developed model potentially improves the reliability of predicted emission potentials. The model could become a standard screening tool for old landfills if its applicability and reliability would be tested in additional case studies. 相似文献
267.
Badreddine Sellami Hela Louati Mohamed Dellali Patricia Aissa Ezzeddine Mahmoudi Ana Varela Coelho David Sheehan 《Environmental science and pollution research international》2014,21(6):4461-4472
The effects of permethrin (PER) on a panel of antoxidant enzymes; superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and indices of protein oxidation status (carbonylation and free thiols) were determined in digestive gland and gills of the clam Ruditapes decussatus. Animals were exposed to 100 ppb PER for 2 days. These enzyme activities increased significantly in digestive gland (p?<?0.05) after PER treatment and oxidative modification of proteins was detected in both gill and digestive gland extracts using redox proteomics. PER exposure significantly reduced the amount of protein free thiol groups in digestive gland rather than in gill, when compared to controls. Conversely, digestive gland showed significantly higher levels of carbonylated proteins than gill after PER exposure. Some proteins were successfully identified by mass spectrometry of tryptic peptides. Our data suggest that digestive gland of R. decussatus can be used as a model tissue for investigating environmental risk of PER contamination. 相似文献
268.
Eric M. Fujita David E. Campbell W. Patrick Arnott Ted Johnson Will Ollison 《Journal of the Air & Waste Management Association (1995)》2014,64(7):743-758
Human exposures to criteria and hazardous air pollutants (HAPs) in urban areas vary greatly due to temporal-spatial variations in emissions, changing meteorology, varying proximity to sources, as well as due to building, vehicle, and other environmental characteristics that influence the amounts of ambient pollutants that penetrate or infiltrate into these microenvironments. Consequently, the exposure estimates derived from central-site ambient measurements are uncertain and tend to underestimate actual exposures. The Exposure Classification Project (ECP) was conducted to measure pollutant concentrations for common urban microenvironments (MEs) for use in evaluating the results of regulatory human exposure models. Nearly 500 sets of measurements were made in three Los Angeles County communities during fall 2008, winter 2009, and summer 2009. MEs included in-vehicle, near-road, outdoor, and indoor locations accessible to the general public. Contemporaneous 1- to 15-min average personal breathing zone concentrations of carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds (VOCs), nitric oxide (NO), nitrogen oxides (NOx), particulate matter (<2.5 μm diameter; PM2.5) mass, ultrafine particle (UFP; <100 nm diameter) number, black carbon (BC), speciated HAPs (e.g., benzene, toluene, ethylbenzene, xylenes [BTEX], 1,3-butadiene), and ozone (O3) were measured continuously. In-vehicle and inside/outside measurements were made in various passenger vehicle types and in public buildings to estimate penetration or infiltration factors. A large fraction of the observed pollutant concentrations for on-road MEs, especially near diesel trucks, was unrelated to ambient measurements at nearby monitors. Comparisons of ME concentrations estimated using the median ME/ambient ratio versus regression slopes and intercepts indicate that the regression approach may be more accurate for on-road MEs. Ranges in the ME/ambient ratios among ME categories were generally greater than differences among the three communities for the same ME category, suggesting that the ME proximity factors may be more broadly applicable to urban MEs.
Implications:Estimates of population exposure to air pollutants extrapolated from ambient measurements at ambient fixed site monitors or exposure surrogates are prone to uncertainty. This study measured concentrations of mobile source air toxics (MSAT) and related criteria pollutants within in-vehicle, outdoor near-road, and indoor urban MEs to provide multipollutant ME measurements that can be used to calibrate regulatory exposure models. 相似文献
269.
Amvrossios C. Bagtzoglou Eric D. Kenney April Hiscox David R. Miller 《Environmental Forensics》2014,15(2):147-158
This work applies optimization and an Eulerian inversion approach presented by Bagtzoglou and Baun in 2005 in order to reconstruct contaminant plume time histories and to identify the likely source of atmospheric contamination using data from a real test site for the first time. Present-day distribution of an atmospheric contaminant plume as well as data points reflecting the plume history allow the reconstruction and provide the plume velocity, distribution, and probable source. The method was tested to a hypothetical case and with data from the Forest Atmosphere Transfer and Storage (FACTS) experiment in the Duke experimental forest site. In the scenarios presented herein, as well as in numerous cases tested for verification purposes, the model conserved mass, successfully located the peak of the plume, and managed to capture the motion of the plume well but underestimated the contaminant peak. 相似文献
270.
Innocent Jayawardene Marc Chenier H. David Gardner 《Journal of the Air & Waste Management Association (1995)》2014,64(9):1028-1037
This study investigates the application of the Aerosol-to-Liquid Particle Extraction System (ALPXS), which uses wet electrostatic precipitation to collect airborne particles, for multi-element indoor stationary monitoring. Optimum conditions are determined for capturing airborne particles for metal determination by inductively coupled plasma–mass spectrometry (ICP-MS), for measuring field blanks, and for calculating limits of detection (LOD) and quantification (LOQ). Due to the relatively high flow rate (300 L min?1), a sampling duration of 1 hr to 2 hr was adequate to capture airborne particle-bound metals under the investigated experimental conditions. The performance of the ALPXS during a building renovation demonstrated signal-to-noise ratios appropriate for sampling airborne particles in environments with elevated metal concentrations, such as workplace settings. The ALPXS shows promise as a research tool for providing useful information on short-term variations (transient signals) and for trapping particles into aqueous solutions where needed for subsequent characterization. As the ALPXS does not provide size-specific samples, and its efficiency at different flow rates has yet to be quantified, the ALPXS would not replace standard filter-based protocols accepted for regulatory applications (e.g., exposure measurements), but rather would provide additional information if used in conjunction with filter based methods.
ImplicationsThis study investigates the capability of the Aerosol-to-Liquid Particle Extraction System (ALPXS) for stationary sampling of airborne metals in indoor workplace environments, with subsequent analysis by ICP-MS. The high flow rate (300 L/min) permits a short sampling duration (< 2 hr). Results indicated that the ALPXS was capable of monitoring short-term changes in metal emissions during a renovation activity. This portable instrument may prove to be advantageous in occupational settings as a qualitative indicator of elevated concentrations of airborne metals at short time scales. 相似文献