全文获取类型
收费全文 | 22789篇 |
免费 | 248篇 |
国内免费 | 224篇 |
专业分类
安全科学 | 712篇 |
废物处理 | 1133篇 |
环保管理 | 2940篇 |
综合类 | 2961篇 |
基础理论 | 5876篇 |
环境理论 | 7篇 |
污染及防治 | 6121篇 |
评价与监测 | 1808篇 |
社会与环境 | 1545篇 |
灾害及防治 | 158篇 |
出版年
2023年 | 100篇 |
2022年 | 229篇 |
2021年 | 243篇 |
2020年 | 161篇 |
2019年 | 203篇 |
2018年 | 381篇 |
2017年 | 377篇 |
2016年 | 590篇 |
2015年 | 433篇 |
2014年 | 636篇 |
2013年 | 1969篇 |
2012年 | 773篇 |
2011年 | 1000篇 |
2010年 | 926篇 |
2009年 | 910篇 |
2008年 | 1000篇 |
2007年 | 1112篇 |
2006年 | 984篇 |
2005年 | 810篇 |
2004年 | 804篇 |
2003年 | 810篇 |
2002年 | 736篇 |
2001年 | 965篇 |
2000年 | 678篇 |
1999年 | 431篇 |
1998年 | 307篇 |
1997年 | 283篇 |
1996年 | 325篇 |
1995年 | 298篇 |
1994年 | 288篇 |
1993年 | 262篇 |
1992年 | 263篇 |
1991年 | 227篇 |
1990年 | 228篇 |
1989年 | 233篇 |
1988年 | 213篇 |
1987年 | 176篇 |
1986年 | 137篇 |
1985年 | 157篇 |
1984年 | 181篇 |
1983年 | 169篇 |
1982年 | 212篇 |
1981年 | 157篇 |
1980年 | 133篇 |
1979年 | 165篇 |
1978年 | 130篇 |
1977年 | 118篇 |
1976年 | 106篇 |
1975年 | 88篇 |
1974年 | 94篇 |
排序方式: 共有10000条查询结果,搜索用时 658 毫秒
991.
S. Alfieri U. Amato M.F. Carfora M. Esposito V. Magliulo 《Atmospheric environment (Oxford, England : 1994)》2010,44(15):1866-1876
Quantifying trace gas emissions and the influence of surface exchange processes on the atmosphere is a necessary step towards the control of global greenhouse gas emissions and reliability of air quality models. This paper proposes a procedure based on the mass balance method and implemented on highly resolved aircraft data. It allows one to estimate surface exchanges on areas of several km2 and heterogeneous features exploiting the characteristics of convective boundary layer during steady state conditions that permit the estimation of emission/absorption terms as functions of advective fluxes only. A nonparametric approach is adopted and the fluxes on the surface of a virtual box surrounding the area of interest are reconstructed on the basis of scalar densities and wind vectors using Shepard functions. Two different techniques are also proposed to face lack of data on the top surface of the box. The method has been applied to experimental data coming from measurement campaigns on two different sites. It provides realistic estimates of the CO2 emission/absorption in the considered areas that are in good agreement with CO2 fluxes evaluated by Airborne Eddy Covariance and confirm the suitability of the proposed approach for the assessment of turbulent exchange of trace gases by composite landscapes. Uncertainties on the estimated emissions due to both propagation of the experimental error and interpolation have been quantified by bootstrap analysis as 6%. 相似文献
992.
993.
The effect of invertebrate predation pressure by the cladoceran Leptodora kindti on the population structure of Daphnia galeata and D. hyalina has been estimated by analyzing the occurrence frequency of the normal and spined morphotypes in Lake Baikal. It is shown
that the growth of L. kindti population density leads to an increase in the proportion of the spined morphotype, while that of that of the normal morphotype
decreases. 相似文献
994.
Distribution of 238U and 226Ra in soils and plants of an industrially polluted area are considered. The dependence between the biological uptake coefficients
(BUCs) for the plant species studied and the radionuclide concentrations in soil can be approximated by a decreasing power
function. Species differences in radionuclide uptake are demonstrated. 相似文献
995.
V. N. Orlov Yu. M. Borisov S. Yu. Irkhin A. A. Kovaleva 《Russian Journal of Ecology》2010,41(6):519-523
The distribution of three chromosome races (Moscow, Western Dvina, and Seliger) of the common shrew Sorex araneus L. in the zone of contact between their ranges in the Valdai Heights (32°00′ E, 57°00′ N) is discussed. The area co-inhabited
by all the three races is extremely small. Representatives of all the three races have been captured on only one trap line,
although there are no obstacles to the expansion of shrews. The extremely small area co-inhabited by the three races, as well
as the strictly parapatric distribution of the Moscow and Western Dvina races, may be related with competition forms such
as avoidance of contacts and separation of ecological niches. 相似文献
996.
997.
James W. Rivers Philip S. Gipson Donald P. Althoff Jeffrey S. Pontius 《Environmental management》2010,45(2):203-216
Military training activities are known to impact individual species, yet our understanding of how such activities influence
animal communities is limited. In this study, we used long-term data in a case study approach to examine the extent to which
the local small landbird community differed between a site in northeast Kansas that experienced intensive disturbance from
military training activities (Ft. Riley Military Installation) and a similar, nearby site that experienced minimal human disturbance
(Konza Prairie Biological Station). In addition, we characterized how the regional pool of potential colonizers influenced
local community dynamics using Breeding Bird Survey data. From 1991 to 2001, most species of small terrestrial landbirds (73%)
recorded during breeding surveys were found at both sites and the mean annual richness at Ft. Riley (39.0 ± 2.86 [SD]) was
very similar to that of Konza Prairie (39.4 ± 2.01). Richness was maintained at relatively constant levels despite compositional
changes because colonizations compensated local extinctions at both sites. These dynamics were driven primarily by woodland
species that exhibited stochastic losses and gains and were present at a low local and regional abundance. Our results suggest
that military training activities may mimic natural disturbances for some species in this area because the small landbird
community did not differ markedly between sites with and sites without extensive human disturbance. Although our results suggest
that military training is not associated with large changes in the avian community, additional studies are needed to determine
if this pattern is found in other ecological communities. 相似文献
998.
Michael J. White Daniel E. Storm Philip Busteed Scott Stoodley Shannon J. Phillips 《Environmental management》2010,45(5):1164-1174
In the United States, many state and federally funded conservation programs are required to quantify the water quality benefits
resulting from their efforts. The objective of this research was to evaluate the impact of conservation practices subsidized
by the Oklahoma Conservation Commission on phosphorus and sediment loads to Lake Wister. Conservation practices designed to
increase vegetative cover in grazed pastures were evaluated using Landsat imagery and the Soil and Water Assessment Tool (SWAT).
Several vegetative indices were derived from Landsat imagery captured before and after the implementation of conservation
practices. Collectively, these indicators provided an estimate of the change in vegetative soil cover attributable to conservation
practices in treated fields. Field characteristics, management, and changes in vegetative cover were used in the SWAT model
to simulate sediment and phosphorus losses before and after practice implementation. Overall, these conservation practices
yielded a 1.9% improvement in vegetative cover and a predicted sediment load reduction of 3.5%. Changes in phosphorus load
ranged from a 1.0% improvement to a 3.5% increase, depending upon initial vegetative conditions. The use of fertilizers containing
phosphorus as a conservation practice in low-productivity pastures was predicted by SWAT to increase net phosphorus losses
despite any improvement in vegetative cover. This combination of vegetative cover analysis and hydrologic simulation was a
useful tool for evaluating the effects of conservation practices at the basin scale and may provide guidance for the selection
of conservation measures subsidized in future conservation programs. 相似文献
999.
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
1000.
María Luz Martín-Peña José María Sánchez-López 《Journal of Environmental Planning and Management》2010,53(3):297-315
Drawing on Ajzen's Theory of Planned Behaviour, this paper analyses whether there is a relation between management's behavioural intentions toward an environmental problem and the company's specific actions in this area, and also considers the impact of the company size on these actions. For the data, a questionnaire was sent to 184 managers employed in industrial companies located in Spain which belonged to the automobile industry. The empirical analysis produces positive and significant regression coefficients and provides support for the hypotheses proposed. Specifically, the results show that the environmental actions carried out in the company respond at least in part to management's behavioural intentions toward these issues and the size of the firm. 相似文献