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101.
The presence of natural estrogen hormones as trace concentrations in the environment has been reported by many researchers
and is of growing concern due to its possible adverse effects on the ecosystem. In this study, municipal biosolids, poultry
manure (PM) and cow manure (CM), and spent mushroom compost (SMC) were analyzed for the presence of seven estrogen hormones.
17α-estradiol, 17β-estradiol, 17α-dihydroequilin, and estrone were detected in the sampled biosolids and manures at concentrations
ranging from 6 to 462 ng/g of dry solids. 17α-estradiol, 17β-estradiol, and estrone were also detected in SMC at concentrations
ranging from 4 to 28 ng/g of dry solids. Desorption experiments were simulated in the laboratory using deionized water (milli-Q),
and the aqueous phase was examined for the presence of estrogen hormones to determine their desorption potential. Very low
desorption of 0.4% and 0.2% estrogen hormones was observed from municipal biosolids and SMC, respectively. An estimate of
total estrogen contribution from different solid waste sources is reported. Animal manures (PM and CM) contribute to a significant
load of estrogen hormones in the natural environment. 相似文献
102.
As facile “environmental media”, the outdoor dust may reflect the changes of contaminants in environment more promptly. In
the present study, selected organochlorine contaminants (OCs) include hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes
(DDTs), hexachlorobenzene (HCB), and pentachlorobenzene (PeCB) were detected in 20 outdoor dust samples collected from Xinxiang
City. The concentrations of ΣHCHs, ΣDDTs, HCB, and PeCB in dust were in the range of 0.18–5.05 ng/g dry weight, 0.44–13.50 ng/g
dry weight, 0.13–51.61 ng/g dry weight and ND-0.74 ng/g dry weight, respectively. Long-range transport, historical use, and
recent impact of impure pesticides might be the main sources of OCs in the outdoor dust. The results of this study indicated
that impure pesticide application maybe an important source of DDTs and HCB in the environment. 相似文献
103.
This article sets out to analyse how and to what degree land use is linked to the physical characteristics of the territory
itself, and the way in which changes in land use are determined by agricultural and socio-demographic dynamics. The study
was conducted within the territorial boundaries of five municipalities surrounding Lake Trasimeno and refers to the periods
1977–2000 for land use and 1971–2001 for socio-demography data. The use of environmental, social, economic and agricultural
indicators demonstrates how a mix of various indicators are useful for monitoring the changes which took place. It also shows
the powerful influence that socio-demographic factors exert upon land use and landscape change. 相似文献
104.
Spatial and seasonal distribution of nitrogen in marsh soils of a typical floodplain wetland in Northeast China 总被引:3,自引:0,他引:3
Bai J Wang Q Deng W Gao H Tao W Xiao R 《Environmental monitoring and assessment》2012,184(3):1253-1263
Horizontal and profile distributions of nitrogen in marsh soils in different seasons were studied in a typical site within
the Erbaifangzi wetland in Northeast China. Results showed that there was higher spatial heterogeneity for nitrate nitrogen
(NO3--_{3}^{-}-N) and ammonium nitrogen (NH4+_{4}^{+}–N), as well as available nitrogen (AN), in surface soils in July compared to that in September. Relative to July, the mean
nitrogen contents in surface soils were slightly higher in September; however, in November, soils contained significantly
lower NO3--_{3}^{-}-N and NH4+_{4}^{+}–N, higher AN, organic nitrogen (Org-N), and total nitrogen (TN). Except for mineral nitrogen, no significant differences
were observed between Org-N and TN contents in September and November. Nitrogen contents generally declined exponentially
with depth along soil profiles in three sampling dates (July, September, and November), except for a significant accumulation
peak of NO3--_{3}^{-}-N at the 20–30 cm depth in September. However, NH4+_{4}^{+}–N contents showed a vertical alternation of “increasing and decreasing” in both July and September, while nearly kept constant
with depth in November. The depth ranking of nitrogen showed the shallowest distribution for AN, followed by Org-N and TN,
while deeper distributions for NO3--_{3}^{-}-N and NH4+_{4}^{+}–N. TN, Org-N, and AN were significantly correlated with soil organic matter and total phosphorus. Soil pH values were significantly
correlated with TN and AN contents in surface soils. Clay contents showed significant correlations with nitrogen contents
except for NO3--_{3}^{-}-N in surface soils and NH4+_{4}^{+}–N in profile soils. However, soil moisture was not significantly correlated with nitrogen contents among all soil samples. 相似文献
105.
Mehmet Sinan Bilgili Gamze Varank Elif Sekman Selin Top Didem Özçimen Remziye Yazıcı 《Environmental Modeling and Assessment》2012,17(3):289-300
Since phenols and phenolic compounds in many industrial wastewaters are toxic organic contaminants for humans and aquatic
life, to remove these compounds via the most efficient way is very important for environmental remediation treatment. In this
context, almost all of the isotherm models (Freundlich, Langmuir, Temkin, Redlich–Peterson, Sips, and Khan) for adsorption
in the literature were applied to explain the adsorption mechanism of 4-chlorophenol on activated carbon in this study. Also
theoretical modeling data were obtained using model equations; interpolation and analysis of variance were made to compare
data by using statistics software. In addition, the thermodynamic and kinetic studies for adsorption mechanism were included
in the article. The adsorption of 4-chlorophenol on activated carbon fits well to the pseudo-first-order kinetic model than
the pseudo-second-order, intraparticular diffusion and Bangham models. It is also indicated that 4-chlorophenol adsorption
by granular activated carbon would be attributed to a type of transition between physical and chemical adsorption rather than
a pure physical or chemical adsorption process. As a result, an environmental remediation problem and the adsorption mechanism
on activated carbon that can be regarded as a solution to this problem are described and explained using the mathematical
models and calculations in this study. 相似文献
106.
de Andrade Brito I Arruda Freire C Yamamoto FY Silva de Assis HC Rodrigues Souza-Bastos L Cestari MM de Castilhos Ghisi N Prodocimo V Filipak Neto F de Oliveira Ribeiro CA 《Journal of environmental monitoring : JEM》2012,14(2):615-625
Paraíba do Sul River is located at a very densely inhabited region of Brazil crossing the three most industrialized states of the country (S?o Paulo, Minas Gerais and Rio de Janeiro states). As a result, industrial and farming residues as well as urban sewage are frequently disposed without appropriate treatment. The current study aimed at investigating the water quality in three reservoirs along the Paraíba do Sul River (Ilha dos Pombos, Santa Cecília and Santa Branca), through physiological, morphological, biochemical, and genetic biomarkers. The bioindicator chosen was the catfish Pimelodus maculatus, sampled during the dry (June 2008) and rainy (February 2009) seasons. Also, some water physicochemical parameters were analyzed from the sampling sites, but displayed no alterations according to the Brazilian Agency for Water Quality Legislation. Branchial carbonic anhydrase activity was inhibited in the dry season, while renal carbonic anhydrase activity was inhibited in the rainy season in the Santa Branca reservoir, indicating disturbance of osmoregulatory and acid-base regulation processes. Histopathological alterations were observed in the gills (neoplasic and tissue hyperplasia processes) and liver (necrosis), indicating serious damage to the functional integrity of these organs. A high incidence of melanomacrophage centers was observed in the liver, suggesting an intense immune response in all reservoirs. Acetylcholinesterase and catalase activity showed also differences corroborating some morphological results. Likewise, the induction of the micronucleus and DNA damage indicate genotoxicity, but mainly in the Santa Branca reservoir. Thus, the health status of P. maculatus warrants caution in the use of the water from the 3 reservoirs for direct human consumption, particularly after the accidental spill of endosulfan in November 2008, three months before the rainy season sampling. 相似文献
107.
Maria P. Papadopoulou Emmanouil A. Varouchakis George P. Karatzas 《Environmental Modeling and Assessment》2010,15(5):319-328
Karst aquifers are characterized by spatial heterogeneity due to the presence of highly permeable channels and conduits in
low-permeable fractured rocks (matrix block). Recent studies have reported a close relationship between surface and subsurface
water in karstic regions due to the water flow through a complicated network of paths formed by fracture intersections. Subsurface
flow in karstified aquifers ranges between conduit flow, in large passages with relatively high flow velocities, and diffuse
flow, in the matrix block where Darcy’s law is still valid. In this paper, we present the simulation of a complex karstified
aquifer system in Crete, Greece, where the presence of main faults drastically affects the regional flow. A discrete fracture
approach in conjunction with an equivalent porous medium approach was adopted to simulate the mixed flow in the area of interest.
The simulation results have shown that the length and the orientation of the dominant faults, primarily during the rainy season,
affect the flow field. 相似文献
108.
Michael G. Hutchins Amelie Deflandre-Vlandas Paulette E. Posen Helen N. Davies Colin Neal 《Environmental Modeling and Assessment》2010,15(2):93-109
A combined semi-distributed hydrological model (CASCADE/QUESTOR) is used to evaluate the steady-state that may be achieved
after changes in land-use or management and to explore what additional factors need to be considered in representing catchment
processes. Two rural headwater catchments of the River Derwent (North Yorkshire, UK) were studied where significant change
in land-use occurred in the 1990s and the early 2000s. Much larger increases in mean nitrate concentration (55%) were observed
in the catchment with significant groundwater influence (Pickering Beck) compared with the surface water-dominated catchment
(13% increase). The increases in Pickering Beck were considerably greater than could be explained by the model in terms of
land-use change. Consequently, the study serves to focus attention on the long-term increases in nitrate concentration reported
in major UK aquifers and the ongoing and chronic impact this trend is likely to be having on surface water concentrations.
For river environments, where groundwater is a source, such trends will mask the impact of measures proposed to reduce the
risk of nitrate leaching from agricultural land. Model estimates of within-channel losses account for 15–40% of nitrate entering
rivers. 相似文献
109.
Ans M. Mouton Andy P. Dedecker Sovan Lek Peter L. M. Goethals 《Environmental Modeling and Assessment》2010,15(1):65-79
This study aimed to compare different methods to analyse the contribution of individual river characteristics to predict the
abundance of Asellus (Crustacea, Isopoda). Six methods which provide the relative contribution and/or the contribution profile of the input variables
of artificial neural network models were therefore compared: (1) the ‘partial derivatives’ method; (2) the ‘weights’ method;
(3) the ‘perturb’ method; (4) the ‘profile’ method; (5) the ‘classical stepwise’ method; (6) the ‘improved stepwise’ method.
Consequently, the key variables which affect the habitat preferences of Asellus could be identified. To evaluate the performance of the artificial neural network model, the model predictions were compared
with the results of a multiple linear regression analysis. The dataset consisted of 179 samples, collected over a 3-year period
in the Zwalm catchment in Flanders, Belgium. Twenty-four environmental variables as well as the log-transformed abundance
of Asellus were used in this study. The different contribution methods seemed to give similar results concerning the order of importance
of the input variables. Nevertheless, their diverse computation led to differences in sensitivity and stability of the methods
and the derived outcomes on the habitat preferences. From an ecological point of view, the environmental variables describing
the stream type (width, depth, stream order and distance to mouth) were the most significant variables for Asellus in the Zwalm catchment during the period 2000–2002 for all applied methods. Indirectly, one can conclude that the water quality
is not the limiting factor for the survival of Asellus in the Zwalm catchment. 相似文献
110.
In the event of a natural or anthropogenic disturbance, environmental resource managers require a reliable tool to quickly
assess the spatial extent of potential damage to the seagrass resource. The temporal availability of the Landsat 5 Thematic
Mapper (TM) imagery provided a suitable option to detect and assess damage of the submerged aquatic vegetation (SAV). This
study examined Landsat TM imagery classification techniques to create two-class (SAV presence/absence) and three-class (SAV
estimated coverage) SAV maps of the seagrass resource. The Mahalanobis Distance method achieved the highest overall accuracy
(86%) and validation accuracy (68%) for delineating the seagrass resource (two-class SAV map). The Maximum Likelihood method
achieved the highest overall accuracy (74%) and validation accuracy (70%) for delineating the seagrass resource three-class
SAV map. The Landsat 5 TM imagery classification provided a seagrass resource map product with similar accuracy to the aerial
photointerpretation maps (validation accuracy 71%). The results support the application of remote sensing methods to analyze
the spatial extent of the seagrass resource. 相似文献