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671.
Sahoo SK Chahil GS Mandal K Battu RS Singh B 《Journal of environmental science and health. Part. B》2012,47(1):42-50
Dissipation of β-cyfluthrin and imidacloprid in okra was studied following three applications of a combination formulation of Solomon 300 OD (β-cyfluthrin 9 % + imidacloprid 21 %) @ 60 and 120 g a.i. ha(-1) at 7 days interval. Residues of β-cyfluthrin and imidacloprid in okra were estimated by gas liquid chromatography (GLC) and high performance liquid chromatography (HPLC), respectively. Residues of β-cyfluthrin were confirmed by gas chromatograph-mass spectrometry (GC-MS) and that of imidacloprid by high performance thin layer chromatography (HPTLC). Half-life periods for β-cyfluthrin were found to be 0.91 and 0.68 days whereas for imidacloprid these values were observed to be 0.85 and 0.96 days at single and double the application rates, respectively. Residues of β-cyfluthrin dissipated below its limit of quantification (LOQ) of 0.01 mg kg(-1) after 3 and 5 days at single and double the application dosage, respectively. Similarly, residues of imidacloprid took 5 and 7 days to reach LOQ of 0.01 mg kg(-1), at single and double dosages respectively. Soil samples collected after 15 days of the last application did not show the presence of β-cyfluthrin and imidacloprid at their detection limit of 0.01 mg kg(-1). 相似文献
672.
Plant available nitrogen, belowground (root) biomass, soil nitrogen (N) mineralization and microbial biomass N (MBN) were studied for 12 years at the interval of 2 years (0, 2, 4, 6, 8, 10 and 12?years) and mine dump stability at the intervals of 6 years (0, 6 and 12?years) after re-vegetation on coal mine spoil site. Plant available nitrogen in revegetated mine spoil ranged from 4.51 to 6.59?μg?g(-1), net N-mineralization from 1.87 to 13.85?μg?g(-1)?month(-1), MBN from 10 to 22.63?μg?g(-1), and root biomass from 28 to 566 g(-2). Mining activity has caused a change in soil characteristics including plant available nutrients like nitrate-N, ammonium-N and phosphate-P by 70, 67, and 76?%, respectively, N-mineralization by 93?%, root biomass values by 97?% and MBN values by 91?% compared to forest ecosystems. Revegetation of mine spoil produced increase in root biomass values by 1.3, 7.6 and 17.2 times, mineral N values by 1.22, 1.43 and 1.79 times, N-mineralization values by 1.8, 5.2 and 12.6 times and MBN values by 1.6, 2.0, and 3.4 times in 2, 6 and 12?years, respectively. Below ground biomass was highly co-related with microbial biomass and plant available nutrients. N-mineralization, plant available nutrients and the clay content were positively correlated with age of revegetation (P?0.01). From the numerical modelling it was analyzed that revegetation increased the dump slope stability with a factor of safety of 1.7 and 2.1 after 6 and 12?years of plantation on dump slope, respectively, while it was 1.2 before revegetation. Thus, long term revegetation was found to have direct impact on dump stability and indirect impact on soil fertility status in mine spoil, where plant biomass and microbial biomass provide major contributions in ecological redevelopment of the mine spoil. 相似文献
673.
This study reports how Traditional Ecological Knowledge (TEK) and informal cultural institutions have conserved key varieties
of the wildgrowing rice, ‘tinni’ (red rice, or brownbeard rice, Oriza rufipogon Griff.), within the Bhar community of eastern Uttar Pradesh, India. The study was conducted, using conventional and participatory
methods, in 10 purposively selected Bhar villages. Two distinct varieties of tinni (‘tinni patali’ and ‘tinni moti’) with differing habitats and phenotypic characters were identified. Seven microecosystems (Kari, Badaila, Chammo, Karmol,
Bhainsiki, Bhainsala and Khodailia) were found to support these varieties in differing proportions. Tinni rice can withstand more extreme weather conditions (the highest as well as lowest temperatures and rainfall regimes) than
the ‘genetically improved’ varieties of rice (Oriza sativa L.) grown in the region. Both tinni varieties are important bioresources for the Bhar’s subsistence livelihoods, and they use distinctive conservation approaches
in their maintenance. Bhar women are the main custodians of tinni rice agrobiodiversity, conserving tinni through an institution called Sajha. Democratic decision-making at meetings organized by village elders determines the market
price of the tinni varieties. Overall, the indigenous institutions and women’s participation seem to have provided safeguards from excessive
exploitation of tinni rice varieties. The maintenance of tinni through cultural knowledge and institutions serves as an example of the importance of locally maintained crop varieties in
contributing to people’s resilience and food security in times of rapid social and environmental change. 相似文献
674.
Shalini Singh Prem Dureja Sushil Kumar 《Journal of environmental science and health. Part. B》2013,48(3):337-346
Abstract The degradation of α and β isomers of endosulphan and endosulphan sulphate in four sterilized and non sterilized Indian soils under laboratory conditions was studied. Degradation was found to be more in non‐sterilized as compared to the sterilized soil. The half life of α‐endosulphan, β‐endosulphan and endosulphan sulphate was found to be 136.8, 273 and 301 days in sterilized Alfisol and 55, 256 and 277 days in non‐sterilized Alfisol, respectively. α‐Endosulphan degraded more readily than β‐endosulphan and endosulphan sulphate under both sterilized and non‐sterilized soil conditions. 相似文献
675.
Gajendra Singh Biplab Bhattacharya G.N. Tiwari 《International Journal of Sustainable Engineering》2016,9(3):170-181
A modified brushed permanent magnet DC (PMDC) motor has been developed and fabricated for a photovoltaic (PV)-operated solar systems. The conventional PMDC motor has been plagued with constraints, the most critical being ingestion of vapours of working fluid inside the rotor and stator, damaging the insulation of windings and forming a thin film of moisture between commutator and brushes. This flaw results into a very low mean time between failures of the motor. In the past, many attempts have been made where-in variety of seals to isolate the working fluid vapours from inner parts of motor have been tried out, but to no avail. Even Brushless DC motors have been designed in the past but their exorbitant cost makes the entire arrangement not viable economically. The modification attempted in this article overcomes the problem of working fluid ingestion inside the motor. It is found that mass flow rate of working fluid obtained at maximum peak sunshine hours is 17.5 l/min at 3030 rpm of motor driven by a PV module of 40 W at 16.20 V. This low-cost modified PMDC motor has been robust with high mean time between failures as no breakdown observed during 18 months of operation. 相似文献
676.
Kunwar P. Singh Shikha Gupta Priyanka Ojha Premanjali Rai 《Environmental science and pollution research international》2013,20(4):2271-2287
The research aims to develop artificial intelligence (AI)-based model to predict the adsorptive removal of 2-chlorophenol (CP) in aqueous solution by coconut shell carbon (CSC) using four operational variables (pH of solution, adsorbate concentration, temperature, and contact time), and to investigate their effects on the adsorption process. Accordingly, based on a factorial design, 640 batch experiments were conducted. Nonlinearities in experimental data were checked using Brock–Dechert–Scheimkman (BDS) statistics. Five nonlinear models were constructed to predict the adsorptive removal of CP in aqueous solution by CSC using four variables as input. Performances of the constructed models were evaluated and compared using statistical criteria. BDS statistics revealed strong nonlinearity in experimental data. Performance of all the models constructed here was satisfactory. Radial basis function network (RBFN) and multilayer perceptron network (MLPN) models performed better than generalized regression neural network, support vector machines, and gene expression programming models. Sensitivity analysis revealed that the contact time had highest effect on adsorption followed by the solution pH, temperature, and CP concentration. The study concluded that all the models constructed here were capable of capturing the nonlinearity in data. A better generalization and predictive performance of RBFN and MLPN models suggested that these can be used to predict the adsorption of CP in aqueous solution using CSC. 相似文献
677.
Groundwater quality in Imphal West district, Manipur, India, with multivariate statistical analysis of data 总被引:2,自引:0,他引:2
Elangbam J. K. Singh Abhik Gupta N. R. Singh 《Environmental science and pollution research international》2013,20(4):2421-2434
The aim of this paper was to analyze the groundwater quality of Imphal West district, Manipur, India, and assess its suitability for drinking, domestic, and agricultural use. Eighteen physico-chemical variables were analyzed in groundwater from 30 different hand-operated tube wells in urban, suburban, and rural areas in two seasons. The data were subjected to uni-, bi-, and multivariate statistical analysis, the latter comprising cluster analysis (CA), principal component analysis (PCA), and factor analysis (FA). Arsenic concentrations exceed the Indian standard in 23.3 % and the WHO limit in 73.3 % of the groundwater sources with only 26.7 % in the acceptable range. Several variables like iron, chloride, sodium, sulfate, total dissolved solids, and turbidity are also beyond their desirable limits for drinking water in a number of sites. Sodium concentrations and sodium absorption ratio (SAR) are both high to render the water from the majority of the sources unsuitable for agricultural use. Multivariate statistical techniques, especially varimax rotation of PCA data helped to bring to focus the hidden yet important variables and understand their roles in influencing groundwater quality. Widespread arsenic contamination and high sodium concentration of groundwater pose formidable constraints towards its exploitation for drinking and other domestic and agricultural use in the study area, although urban anthropogenic impacts are not yet pronounced. 相似文献
678.
Jiwan Singh Ajay S. Kalamdhad 《Environmental science and pollution research international》2013,20(12):8974-8985
Vermicomposting of water hyacinth is a good alternative for the treatment of water hyacinth (Eichhornia crassipes) and subsequentially, beneficial for agriculture purposes. The bioavailability and leachability of heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd, and Cr) were evaluated during vermicomposting of E. crassipes employing Eisenia fetida earthworm. Five different proportions (trials 1, 2, 3, 4, and 5) of cattle manure, water hyacinth, and sawdust were prepared for the vermicomposting process. Results show that very poor biomass growth of earthworms was observed in the highest proportion of water hyacinth (trial 1). The water soluble, diethylenetriaminepentaacetic acid (DTPA) extractable, and leachable heavy metals concentration (percentage of total heavy metals) were reduced significantly in all trials except trial 1. The total concentration of some metals was low but its water soluble and DTPA extractable fractions were similar or more than other metals which were present in higher concentration. This study revealed that the toxicity of metals depends on bioavailable fraction rather than total metal concentration. Bioavailable fraction of metals may be toxic for plants and soil microorganisms. The vermicomposting of water hyacinth by E. fetida was very effective for reduction of bioavailability and leachability of selected heavy metals. Leachability test confirmed that prepared vermicompost is not hazardous for soil, plants, and human health. The feasibility of earthworms to mitigate the metal toxicity and to enhance the nutrient profile in water hyacinth vermicompost might be useful in sustainable land renovation practices at low-input basis. 相似文献
679.
Atrazine degrading enrichment culture was prepared by its repeated addition to an alluvial soil and its ability to degrade atrazine in mineral salts medium and soil was studied. Enrichment culture utilized atrazine as a sole source of carbon and nitrogen in mineral salts medium and degradation slowed down when sucrose and/or ammonium hydrogen phosphate were supplemented as additional source of carbon and nitrogen, respectively. Biuret was detected as the only metabolite of atrazine while deethylatrazine, deisopropyatrazine, hydroxyatrazine and cyanuric acid were never detected at any stage of degradation. Enrichment culture degraded atrazine in an alkaline alluvial soil while no degradation was observed in the acidic laterite soil. Enrichment culture was able to withstand high concentrations of atrazine (110 μg/g) in the alluvial soil as atrazine was completely degraded. Developed mixed culture has the ability to degrade atrazine and has potential application in decontamination of contaminated water and soil. 相似文献
680.
Sharma KK Dubey JK Deka SC Chandrasekaran S Kalpana Gupta P Kumar A Vandana Devi MJ Singh B Baruah AA Kennedy JS Sharma ID Patyal SK Nath A 《Chemosphere》2007,68(4):790-796
Spiromesifen (Oberon) is a new insecticide and miticide of chemical class ketoenol active against white flies (Bemisia spp., Trialeuroides spp.) and spider mites (Tetranychus and Panonychus spp.). Due to its potential significance in insect resistance management, it is important to establish its behaviour on crop and environment. In the present study, the degradation/dissipation of spiromesifen on tea crop under tropical environmental conditions was studied and its DT(50) (t(1/2)), and DT(90) (time to reduce to 90% of the initial value) were estimated. Spiromesifen was sprayed on tea crop after first rain flush at four different locations @ 96 and 192ga.i.ha(-1). Samples of tea leaves were drawn at 0, 1, 3, 5, 7, 10, 15, 21 and 30 days after treatment and that of soil at 10 days after treatment and at harvest from 0 to 15 and 15 to 30cm layers. After crude extraction of tea leaves for spiromesifen residues with acetone:water, the contents were partitioned with cyclohexane:ethyl acetate and cleaned up on Florosil column. Soil residues were also extracted similarly. Quantification of residues was done on GC-MS in Selected Ion Monitoring (SIM) mode in mass range 271-274m/z. The LOQ of this method was found to be 0.05microgg(-1) while LOD being 0.015microgg(-1). The DT(50) of spiromesifen when applied at recommended doses in tea leaves was found to be 5.0-8.5 days. Ninety-nine percent degradation was found to occur within 33-57 days after application. In soil, no residues of spiromesifen were detectable 10 days after treatment. 相似文献