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排序方式: 共有1223条查询结果,搜索用时 515 毫秒
261.
Shashi B. Singh Irani Mukherjee Jaya Maisnam Praveen Kumar Madhuban Gopal Gita Kulshrestha 《Journal of environmental science and health. Part. B》2013,48(4):300-306
Studies were conducted to analyze the residue of commonly used pesticides viz. methyl parathion, chloropyrifos, endosulfan, cypermethrin, fenvalerate, carbendazim, imidacloprid and carbaryl in mango, Dashehari variety, integrated pest management (IPM) and non-IPM samples were collected from the IPM and non-IPM orchards, Lucknow, India. We also present a method for the simultaneous determination of these pesticides in mango samples. Residues of methyl parathion, chloropyriphos, endosulfan, cypermethrin, fenvalerate were extracted from the samples with acetone: cyclohexane: ethyl acetate in the ratio 2:1:1 followed by cleanup using neutral alumina. Analysis was performed by gas chromatography-electron capture detector (GC-ECD) with a megabore column (OV-1). Residues of carbendazim, imidacloprid and carbaryl were extracted with acetone and after cleanup, analysis was performed by high performance liquid chromatography (HPLC) using photo diode array (PDA) detector. Recoveries of all the pesticides ranged between 72.7 – 110.6%, at 0.1 and 1.0 μg g? 1 level of fortification. The residues detected in non-IPM samples of mango were found to be below the prescribed limits of maximum residue limit (MRL) while IPM samples were free from pesticide residues. 相似文献
262.
Appraisal of salinity and fluoride in a semi-arid region of India using statistical and multivariate techniques 总被引:1,自引:0,他引:1
Suman Mor Surender Singh Poonam Yadav Versha Rani Pushpa Rani Monika Sheoran Gurmeet Singh Khaiwal Ravindra 《Environmental geochemistry and health》2009,31(6):643-655
Various physico-chemical parameters, including fluoride (F−), were analyzed to understand the hydro-geochemistry of an aquifer in a semi-arid region of India. Furthermore, the quality
of the shallow and deep aquifer (using tube well and hand pumps) was also investigated for their best ecological use including
drinking, domestic, agricultural and other activities. Different multivariate techniques were applied to understand the groundwater
chemistry of the aquifer. Findings of the correlation matrix were strengthened by the factor analysis, and this shows that
salinity is mainly caused by magnesium salts as compared to calcium salts in the aquifer. The problem of salinization seems
mainly compounded by the contamination of the shallow aquifers by the recharging water. High factor loading of total alkalinity
and bicarbonates indicates that total alkalinity was mainly due to carbonates and bicarbonates of sodium. The concentration
of F− was found more in the deep aquifer than the shallow aquifer. Further, only a few groundwater samples lie below the permissible
limit of F−, and this indicates a risk of dental caries in the populace of the study area. The present study indicates that regular monitoring
of groundwater is an important step to avoid human health risks and to assess its quality for various ecological purposes. 相似文献
263.
Nandita Singh Lena Q. Ma Joseph C. Vu Anshita Raj 《Environmental pollution (Barking, Essex : 1987)》2009,157(8-9):2300-2305
This study investigated the effects of arsenic on the in vitro activities of the enzymes (nitrate reductase and nitrite reductase) involved in nitrate metabolism in the roots, rhizomes, and fronds of four-month old Pteris vittata (arsenic – hyperaccumulator) and Pteris ensiformis (non-arsenic--hyperaccumulator) plants. The arsenic treatments (0, 150, and 300 μM as sodium arsenate) in hydroponics had adverse effects on the root and frond dry weights, and this effect was more evident in P. ensiformis than in P. vittata. Nitrate reductase and nitrite reductase activities of arsenate-treated plants were reduced more in P. ensiformis than in P. vittata. This effect was accompanied by similar decreases in tissue NO3? concentrations. Therefore, this decrease is interpreted as being indirect, i.e., the consequence of the reduced NO3? uptake and translocation in the plants. The study shows the difference in the tolerance level of the two Pteris species with varying sensitivity to arsenic. 相似文献
264.
Kunwar P. Singh Shikha Gupta Premanjali Rai 《Environmental science and pollution research international》2014,21(9):6001-6015
Groundwater hydrochemistry of an urban industrial region in Indo-Gangetic plains of north India was investigated. Groundwater samples were collected both from the industrial and non-industrial areas of Kanpur. The hydrochemical data were analyzed using various water quality indices and nonparametric statistical methods. Principal components analysis (PCA) was performed to identify the factors responsible for groundwater contamination. Ensemble learning-based decision treeboost (DTB) models were constructed to develop discriminating and regression functions to differentiate the groundwater hydrochemistry of the three different areas, to identify the responsible factors, and to predict the groundwater quality using selected measured variables. The results indicated non-normal distribution and wide variability of water quality variables in all the study areas, suggesting for nonhomogenous distribution of sources in the region. PCA results showed contaminants of industrial origin dominating in the region. DBT classification model identified pH, redox potential, total-Cr, and λ 254 as the discriminating variables in water quality of the three areas with the average accuracy of 99.51 % in complete data. The regression model predicted the groundwater chemical oxygen demand values exhibiting high correlation with measured values (0.962 in training; 0.918 in test) and the respective low root mean-squared error of 2.24 and 2.01 in training and test arrays. The statistical and chemometric approaches used here suggest that groundwater hydrochemistry differs in the three areas and is dominated by different variables. The proposed methods can be used as effective tools in groundwater management. 相似文献
265.
Exploring correlation between redox potential and other edaphic factors in field and laboratory conditions in relation to methane efflux. 总被引:1,自引:0,他引:1
S N Singh 《Environment international》2001,27(4):265-274
Methane is primarily a biogenic gas, which is implicated in global warming. Although its production in the anoxic conditions is regulated by several edaphic factors, aquatic macrophytes also influence methane emission by providing aerenchyma to act as chimney for CH4 transport from the sediment to troposphere, by releasing root exudates to the sediment to serve as substrate for methanogenic bacteria and by transporting atmospheric O2 to rhizosphere, which stimulates CH4 consumption. Among the edaphic factors, redox potential (Eh) is the most important, which largely determines the action of methanogenic bacteria. Hence, a study was undertaken first to find out the correlation between CH4 emission and edaphic factors in the field conditions and then to understand the relationship between Eh and other edaphic factors. The field studies revealed that natural wetlands were the major source of CH4 emission, and the vegetation plays an important role in CH4 emission from the water bodies. However, it was very difficult to establish a strong relationship between the CH4 emission and the edaphic factors in the field conditions due to other limiting factors and their constant fluctuations. In this connection, the laboratory experiments exhibited that soil temperature, pH, moisture regime and incubation period were negatively correlated with Eh, which determines the initiation of methanogenic process. However, organic carbon and the water regime over the soil surface did not show any impact on Eh in this study. 相似文献
266.
Abhishek Sanskrityayn Vijay P. Singh Vinod Kumar Bharati Naveen Kumar 《Environmental Fluid Mechanics》2018,18(3):739-757
In the present study analytical solutions of a two-dimensional advection–dispersion equation (ADE) with spatially and temporally dependent longitudinal and lateral components of the dispersion coefficient and velocity are obtained using Green’s Function Method (GFM). These solutions describe solute transport in infinite horizontal groundwater flow, assimilating the spatio-temporal dependence of transport properties, dependence of dispersion coefficient on velocity, and the particulate heterogeneity of the aquifer. The solution is obtained in the general form of temporal dependence and the source term, from which solutions for instantaneous and continuous point sources are derived. The spatial dependence of groundwater velocity is considered non-homogeneous linear, whereas the dispersion coefficient is considered proportional to the square of spatial dependence of velocity. An asymptotically increasing temporal function is considered to illustrate the proposed solutions. The solutions are validated with the existing solutions derived from the proposed solutions in three special cases. The effect of spatially/temporally dependent heterogeneity on the solute transport is also demonstrated. To use the GFM, the ADE with spatio-temporally dependent coefficients is reduced to a dispersion equation with constant coefficients in terms of new position variables introduced through properly developed coordinate transformation equations. Also, a new time variable is introduced through a known transformation. 相似文献
267.
Singh Digvijay Chaudhary Rubina Karthick Alagar 《Environmental science and pollution research international》2021,28(35):47689-47724
Environmental Science and Pollution Research - Integration of photovoltaic (PV) technologies with building envelopes started in the early 1990 to meet the building energy demand and shave the peak... 相似文献
268.
Nain Anil Lohchab Rajesh Kumar Singh Kulbir Kumari Mikhlesh Saini Jitender Kumar 《Journal of Material Cycles and Waste Management》2021,23(6):2192-2207
Journal of Material Cycles and Waste Management - Recirculation of the leachate using bioreactor technology for in-situ treatment of leachate is an efficient method for reducing the contaminants... 相似文献
269.
K. K. Sharma Saudamini Mohapatra A. K. Ahuja M. Deepa Debi Sharma G. K. Jagdish N. Rashmi R. S. Battu S. K. Sharma Balwinder Singh N. S. Parihar B. N. Sharma V. D. Kale R. V. Nakat A. R. Walnuj Geeta Singh Kuldeep K. Ravivanshi Suneeta Devi Rajbir Noniwal 《Environmental monitoring and assessment》2014,186(6):3633-3639
Supervised field trials following good agricultural practices were conducted at the research farms of four agricultural universities located at four different agroclimatic zones of India to evaluate the persistence and dissipation of flubendiamide and its metabolite, des-iodo flubendiamide, on cabbage. Two spray applications of flubendiamide 480 SC of standard and double dose at the rate of 24 and 48 g a.i. ha?1 were given to the crop at a 15-day interval, and the residues of flubendiamide 2 h after spray were found in the range of 0.107–0.33 and 0.20–0.49 mg kg?1 at respective doses. Residue of des-iodo flubendiamide was not detected in any cabbage sample during study period. No residues were found in the soil samples collected from all treated fields after 15 days of application. On the basis of data generated under All India Network Project on Pesticide Residues, a preharvest interval (PHI) of 10 days has been recommended, and the flubendiamide 480 SC has been registered for its use on cabbage by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of flubendiamide on cabbage has been fixed by the Ministry of Health and Family Welfare, Government of India, under Food Safety Standard Authority of India as 0.05 μg/g after its risk assessment. 相似文献
270.
Jayara D.C. Silva Tamara T.B. Leal Ademir S.F. Araújo Raul M. Araujo Regina L.F. Gomes Wanderley J. Melo Rajeev P. Singh 《Waste management (New York, N.Y.)》2010,30(10):1976-1980
Composting has been recognized as one of the most cost effective and environmentally sound alternatives for organic wastes recycling from long and composted wastes have a potential to substitute inorganic fertilizers. We investigated the potential of composted tannery sludge for ornamental purposes and to examine the effects of two different composts and concentrations on ornamental Capsicum growth. The two composts were produced with tannery sludge and the composition of each compost was: compost1 of tannery sludge (C1TS) – tannery sludge + sugarcane straw and cattle manure mixed in the ratio 1:3:1 (v:v:v); compost2 of tannery sludge (C2TS) – tannery sludge + “carnauba” straw and cattle manure in the ratio 1:3:1 (v:v:v). Each compost was amended with soil at rates (% v:v) of 0%, 25%, 50%, 75% and 100% (designation hereafter as T1–T5, respectively). The number of leaves and fruits were counted, and the stem length was also measured. Chlorophyll content was recorded on three leaves of each harvested plant prior to harvest. Number of leaves and fruits, stem length, dry weight of shoot and roots did not vary significantly between the plants grown in two tannery composts. All the treatments with composted tannery sludge application (T2–T5) significantly increased the number of leaves and fruits, stem length and chlorophyll content compared with the control (T1). The chlorophyll content was higher in plants growing in the C1TS compared to C2TS. The results of the present study further suggest that Capsicum may be a good option to be grown on composted tannery amended soil. 相似文献