全文获取类型
收费全文 | 2891篇 |
免费 | 5篇 |
国内免费 | 30篇 |
专业分类
安全科学 | 56篇 |
废物处理 | 144篇 |
环保管理 | 297篇 |
综合类 | 396篇 |
基础理论 | 1096篇 |
污染及防治 | 567篇 |
评价与监测 | 195篇 |
社会与环境 | 173篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 110篇 |
2017年 | 119篇 |
2016年 | 182篇 |
2015年 | 51篇 |
2014年 | 16篇 |
2013年 | 21篇 |
2012年 | 427篇 |
2011年 | 213篇 |
2010年 | 24篇 |
2009年 | 31篇 |
2008年 | 49篇 |
2007年 | 63篇 |
2006年 | 71篇 |
2005年 | 395篇 |
2004年 | 530篇 |
2003年 | 404篇 |
2002年 | 42篇 |
2001年 | 39篇 |
2000年 | 18篇 |
1999年 | 30篇 |
1998年 | 4篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1979年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1961年 | 2篇 |
1958年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有2926条查询结果,搜索用时 31 毫秒
71.
Chinmoy?JanaEmail author S.?C.?Bhattacharya 《Environment, Development and Sustainability》2017,19(3):921-937
Currently, energy consumption for cooking in rural households of India is mostly based on fuelwood used in traditional stoves. This paper presents results of a study carried out in a forest fringe area of India on cooking energy use. The concept of calculating levelized cost as cost per unit of useful energy is applied on source–device combinations of cooking and validated in Bargaon Community Development Block of Sundergarh District in Odisha, India. About 92 % of the households in the study area use fuelwood as the only energy source for cooking; the total use of fuelwood for only cooking, in the Block is nearly 1.8 times the total sustainable wood supply showing an urgent need for promoting alternative cooking energy options. This paper also presents an assessment of different cooking options in terms of cost per unit of useful cooking energy. LPG, biogas and gasifier stoves are found to be far too expensive for the local people. Briquette-fired improved stoves appear to be a promising cooking energy option in the study area. Government support and intervention are recommended for promoting this option. 相似文献
72.
Poudyal NC Johnson-Gaither C Goodrick S Bowker JM Gan J 《Environmental management》2012,49(3):623-635
Wildland fire in the South commands considerable attention, given the expanding wildland urban interface (WUI) across the
region. Much of this growth is propelled by higher income retirees and others desiring natural amenity residential settings.
However, population growth in the WUI increases the likelihood of wildfire fire ignition caused by people, as humans account
for 93% of all wildfires fires in the South. Coexisting with newly arrived, affluent WUI populations are working class, poor
or otherwise socially vulnerable populations. The latter groups typically experience greater losses from environmental disasters
such as wildfire because lower income residents are less likely to have established mitigation programs in place to help absorb
loss. We use geographically weighted regression to examine spatial variation in the association between social vulnerability
(SOVUL) and wildfire risk. In doing so, we identify “hot spots” or geographical clusters where SOVUL varies positively with
wildfire risk across six Southern states—Alabama, Arkansas, Florida, Georgia, Mississippi, and South Carolina. These clusters
may or may not be located in the WUI. These hot spots are most prevalent in South Carolina and Florida. Identification of
these population clusters can aid wildfire managers in deciding which communities to prioritize for mitigation programming. 相似文献
73.
Chaudhary P Singh SB Chaudhry S Nain L 《Environmental monitoring and assessment》2012,184(2):1145-1156
The present study is aimed at analysing and comparing different soil enzymes in soil samples of native contaminated sites
of a Mathura refinery and adjoining agricultural land. Enzyme activities are considered as indicators of soil quality and
changes in biogeochemical function due to management or perturbations. Soil samples were collected from the premises and nearby
area of Mathura refinery, India. Biological health parameters (dehydrogenase, aryl esterase, aryl sulphatase,
\upbeta \upbeta -glucosidase, alkaline phosphatase, acid phosphatase, lipase, laccase and catalase activity) were estimated in the soil samples.
Among all the samples, sewage sludge soil showed maximum activity of enzymes, microbial biomass carbon and most probable number
of polycyclic aromatic hydrocarbon (PAH) degraders in soils spiked with three- to four-ring PAHs at 50 ppm. Available phosphorus,
potassium and nitrogen was also exceptionally high in this sample, indicating maximum microbial bioconversion due to presence
of nutrients stimulating potent PAH-degrading microorganisms. 相似文献
74.
Minakshi?Sultania Deepak?SrivastavaEmail author 《Journal of Polymers and the Environment》2011,19(4):950-956
Diglycidyl ether of bisphenol—A (DGEBA)—based epoxy resin was blended in the ratio of 3:1 (weight basis) with cycloaliphatic
epoxy (CAE) resin. The prepared blend sample was further blended with different weight percentages of carboxyl-terminated
butadiene acrylonitrile copolymer (CTBN) ranging between 0 and 25 wt% with an interval of 5 wt% and cured with stiochiometric
amounts of 4, 4’- diamino diphenyl sulphone (DDS) cure agent. Structural changes during blending were studied by Fourier-transform
infra-red (FTIR) spectroscopic analysis. The kinetic parameters, viz., order of decomposition reaction (n), activation energy (E), pre-exponential factor (Z) and rate decomposition constant (k), for the decomposition of the samples were calculated by applying Coats-Redfern equation over thermogravimetric (TG) data.
The degradation of each sample followed second-order degradation kinetics, which was calculated by Coats-Redfern equation
using best-fit analysis. This was further confirmed by linear regression analysis. The validity of data was checked by t-test
statistical analysis. Further, the blend sample had higher initial degradation temperature and activation energy than its
respective pure epoxy resin indicating that the CTBN acted as thermal stabilizer for epoxy resin which improved the thermal
stability. 相似文献
75.
Per-and polyfluoroalkyl substances(PFASs) are ubiquitous in sludge and water from waste water treatment plants, as a result of their incorporation in everyday products and industrial processes. In this study, we measured several classes of persistent PFASs,precursors, transformation intermediates, and newly identified PFASs in influent and effluent sewage water and sludge from three municipal waste water treatment plants in Sweden, sampled in 2015. For sludge, samples from 2012 and 2014 were analyzed as well.Levels of precursors in sludge exceeded those of perfluoroalkyl acids and sulfonic acids(PFCAs and PFSAs), in 2015 the sum of polyfluoroalkyl phosphoric acid esters(PAPs) were 15–20 ng/g dry weight, the sum of fluorotelomer sulfonic acids(FTSAs) was 0.8–1.3 ng/g,and the sum of perfluorooctane sulfonamides and ethanols ranged from non-detected to 3.2 ng/g. Persistent PFSAs and PFCAs were detected at 1.9–3.9 ng/g and 2.4–7.3 ng/g dry weight, respectively. The influence of precursor compounds was further demonstrated by an observed substantial increase for a majority of the persistent PFCAs and PFSAs in water after waste water treatment. Perfluorohexanoic acid(PFHxA), perfluorooctanoic acid(PFOA), perfluorohexane sulfonic acid(PFHxS), and perfluorooctane sulfonic acid(PFOS)had a net mass increase in all WWTPs, with mean values of 83%, 28%, 37% and 58%,respectively. The load of precursors and intermediates in influent water and sludge combined with net mass increase support the hypothesis that degradation of precursor compounds is a significant contributor to PFAS contamination in the environment. 相似文献
76.
Antonella?De?DonnoEmail author Tiziana?Grassi Francesco?Bagordo Adele?Idolo Francesca?Serio Giovanni?Gabutti 《Food and environmental virology》2012,4(2):81-88
The purpose of this study was to demonstrate that shellfish can be used to detect enteric viruses in marine waters where they
are present at very low concentrations. Aqua-cultured mussels were placed in the sea just off the mouth of a drainage channel
affected by human and animal faecal contamination. Samples were taken from the channel, the sea and the mussels at intervals
over two 4-week periods. The samples were tested to verify the presence of both rotaviruses and E. coli. Rotaviruses were detected by Real Time-PCR, typed by multiplex PCR and subsequently sequenced. E. coli was enumerated in water matrices by a filtering method and in mussels by the MPN method. The presence of E. coli in the examined matrices demonstrates contamination of faecal origin throughout the studied environments. Rotaviruses were
recorded in channel waters, but not in sea water. In both experiments, rotaviruses were detected in mussels 21 and 28 days
after being placed in the sea water off the channel mouth. The use of mussels thus enabled the detection of rotaviruses in
waters where the high dilution rendered direct investigation impossible. This study indicates that mussels can be used in
marine virological surveillance programs. 相似文献
77.
Simon?BrinerEmail author Michael?Hartmann Robert?Finger Bernard?Lehmann 《Mitigation and Adaptation Strategies for Global Change》2012,17(4):337-355
We assessed the economic suitability of 4 greenhouse gas (GHG) mitigation options and one GHG offset option for an improvement
of the GHG balance of a representative Swiss suckler cow farm housing 35 Livestock units and cultivating 25 ha grassland.
GHG emissions per kilogram meat in the economic optimum differ between the production systems and range from 18 to 21.9 kg
CO2-eq./kg meat. Only GHG offset by agroforestry systems showed the potential to significantly reduce these emissions. Depending
on the production system agroforestry systems could reduce net GHG emissions by 66% to 7.3 kg CO2-eq./kg meat in the most intensive system and by 100% in the most extensive system. In this calculation a carbon sequestration
rate of 8 t CO2/ha/year was assumed. The potential of a combination of the addition of lipids to the diet, a cover of the slurry tank and
the application of nitrification inhibitors only had the potential to reduce GHG emissions by 12% thereby marginal abatement
costs are increasing much faster than for agroforestry systems. A reduction of the GHG emissions to 7.5 kg CO2-eq./kg meat—possible with agroforestry only—raised costs between 0.03 CHF/kg meat and 0.38 CHF/kg meat depending on the production
system and the state of the system before the reduction. If GHG emissions were reduced maximally average costs ranged between
0.37 CHF/kg meat, if agroforestry had the potential to reduce net GHG emissions to 0 kg CO2-eq., to 1.17 CHF/kg meat if also other options had to be applied. 相似文献
78.
Population dynamics and regulation in the cave salamander <Emphasis Type="Italic">Speleomantes strinatii</Emphasis> 总被引:1,自引:0,他引:1
Salvidio S 《Die Naturwissenschaften》2007,94(5):396-400
Time series analysis has been used to evaluate the mechanisms regulating population dynamics of mammals and insects, but has
been rarely applied to amphibian populations. In this study, the influence of endogenous (density-dependent) and exogenous
(density-independent) factors regulating population dynamics of the terrestrial plethodontid salamander Speleomantes strinatii was analysed by means of time series and multiple regression analyses. During the period 1993–2005, S. strinatii population abundance, estimated by a standardised temporary removal method, displayed relatively low fluctuations, and the
autocorrelation function (ACF) analysis showed that the time series had a noncyclic structure. The partial rate correlation
function (PRCF) indicated that a strong first-order negative feedback dominated the endogenous dynamics. Stepwise multiple
regression analysis showed that the only climatic factor influencing population growth rate was the minimum winter temperature.
Thus, at least during the study period, endogenous, density-dependent negative feedback was the main factor affecting the
growth rate of the salamander population, whereas stochastic environmental variables, such as temperature and rainfall, seemed
to play a minor role in regulation. These results stress the importance of considering both exogenous and endogenous factors
when analysing amphibian long-term population dynamics. 相似文献
79.
Vullo R 《Die Naturwissenschaften》2011,98(6):545-549
Sharks are known to have been ammonoid predators, as indicated by analysis of bite marks or coprolite contents. However, body
fossil associations attesting to this predator–prey relationship have never been described so far. Here, I report a unique
finding from the Late Jurassic of western France: a complete specimen of the Kimmeridgian ammonite Orthaspidoceras bearing one tooth of the hybodont shark Planohybodus. Some possible tooth puncture marks are also observed. This is the first direct evidence of such a trophic link between these
two major Mesozoic groups, allowing an accurate identification of both organisms. Although Planohybodus displays a tearing-type dentition generally assumed to have been especially adapted for large unshelled prey, our discovery
clearly shows that this shark was also able to attack robust ammonites such as aspidoceratids. The direct evidence presented
here provides new insights into the Mesozoic marine ecosystem food webs. 相似文献
80.
Some emerging technologies are expected to be pivotal for solving many of the environmental challenges faced today, especially those related to energy. However, many of these technologies may incur significant environmental impacts over their life cycle, while having environmental benefits during their use. This paper presents results of a Life Cycle Assessment (LCA) of a proposed type of nanophotovoltaic, quantum dot photovoltaic (QDPV) module. The LCA is confined to the stages of raw materials acquisition, manufacturing, and use. The impacts of QDPV are compared with other types of PV modules and energy sources - both renewable and nonrenewable. To provide a comprehensive comparative assessment, QDPV modules were compared with mature as well as emerging PV types for which data are available. Comparative assessment with other types of energy sources includes coal, oil, lignite, natural gas, diesel, nuclear, wind, and hydropower.QDPV modules may have the potential to overcome two current barriers of solar technology: low efficiencies and high manufacturing costs. If higher efficiencies are realized, QDPV modules could pave the way to large scale implementation of solar energy, helping nations move toward greater energy independence. On the other hand, candidate materials as quantum dots for solar cell applications are mostly compound semiconductors such as cadmium selenide, cadmium telluride, and lead sulfide which may be toxic and for which renewable options are limited. Toxic effects of these materials may be exacerbated by their nanoscale features.The LCA was carried out using the software SimaPro, and the Ecoinvent Life Cycle Inventory (LCI) database supplemented with available literature and patent information. Our results indicate that while QDPV modules have shorter Energy PayBack Time (EPBT), lower Global Warming Potential (GWP), SOx and NOx emissions than other types of PV modules, they have higher heavy metal emissions, underscoring the need for investigation of emerging technologies, especially nano-based ones, from a life cycle perspective. QDPV modules are better in all impact categories assessed than carbon-based energy sources but they have longer EPBT than wind and hydropower and higher GWP. 相似文献