全文获取类型
收费全文 | 13464篇 |
免费 | 42篇 |
国内免费 | 1049篇 |
专业分类
安全科学 | 303篇 |
废物处理 | 548篇 |
环保管理 | 1228篇 |
综合类 | 3834篇 |
基础理论 | 951篇 |
环境理论 | 1篇 |
污染及防治 | 5241篇 |
评价与监测 | 1473篇 |
社会与环境 | 824篇 |
灾害及防治 | 152篇 |
出版年
2023年 | 33篇 |
2022年 | 40篇 |
2020年 | 31篇 |
2019年 | 29篇 |
2018年 | 35篇 |
2017年 | 56篇 |
2016年 | 39篇 |
2015年 | 107篇 |
2014年 | 61篇 |
2013年 | 56篇 |
2012年 | 1101篇 |
2011年 | 1443篇 |
2010年 | 191篇 |
2009年 | 355篇 |
2008年 | 1351篇 |
2007年 | 1297篇 |
2006年 | 1043篇 |
2005年 | 935篇 |
2004年 | 832篇 |
2003年 | 791篇 |
2002年 | 686篇 |
2001年 | 531篇 |
2000年 | 351篇 |
1999年 | 160篇 |
1998年 | 42篇 |
1997年 | 50篇 |
1996年 | 64篇 |
1995年 | 88篇 |
1994年 | 64篇 |
1993年 | 105篇 |
1992年 | 114篇 |
1991年 | 123篇 |
1990年 | 149篇 |
1989年 | 117篇 |
1988年 | 205篇 |
1987年 | 250篇 |
1986年 | 122篇 |
1985年 | 234篇 |
1984年 | 218篇 |
1983年 | 196篇 |
1982年 | 162篇 |
1981年 | 145篇 |
1980年 | 132篇 |
1979年 | 78篇 |
1978年 | 78篇 |
1977年 | 34篇 |
1976年 | 62篇 |
1975年 | 47篇 |
1974年 | 69篇 |
1973年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
521.
Luo J Shukla R Adhikari A Reponen T Grinshpun SA Zhang Q LeMasters GK 《Journal of environmental monitoring : JEM》2006,8(9):955-962
A time series model was fitted to the pollen concentration data collected in the Greater Cincinnati area for the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS). A traditional time series analysis and temporal variogram approach were applied to the regularly spaced databases (collected in 2003) and irregularly spaced ones (collected in 2002), respectively. The aim was to evaluate the effect of the sampling frequency on the sampling precision in terms of inverse of standard error of the overall level of mean value across time. The presence of high autocorrelation in the data was confirmed and indicated some degree of temporal redundancy in the pollen concentration data. Therefore, it was suggested that sampling frequency could be reduced from once a day to once every several days without a major loss of sampling precision of the overall mean over time. Considering the trade-offs between sampling frequency and the possibility of sampling bias increasing with larger sampling interval, we recommend that the sampling interval should take values from 3 to 5 days for the pollen monitoring program, if the goal is to track the long-term average. 相似文献
522.
Lead concentration in the surface soils from 31 playgrounds in a ward in Tokyo was measured to examine if paint chips, peeled off from playing equipment installed in the playgrounds, contribute to elevated Pb concentration in the soil of public playgrounds. Lead concentration in the paint chips sampled from playgrounds ranged from 0.003 to 8.9%. Lead concentration in the surface soil ranged from 15.2 to 237 mg kg(-1) (average, 55.5 mg kg(-1)) and higher Pb concentration was found in the soil near painted playing equipment indicating that paint chips from playing equipment contributed to increase soil Pb level of playgrounds in Tokyo. The degree of peeling-off of paint on the surface of playing equipment in the public playground (peeling-off index: POI) positively correlated with Pb concentration in the soil (Spearman rank-correlation coefficient, r = 0.366, p = 0.043). The stronger correlation between Pb concentration and isotope ratios (207Pb/206Pb and Pb conc., r = 0.536, p = 0.002, 208Pb/206Pb and Pb conc. r = 0.600, p < 0.001) than that between Pb and POI indicated that gasoline Pb contributed more to the playground-to-playground variation in soil Pb concentration. It was concluded that both gasoline Pb of the past and paint chips contributed to increased Pb concentration in the surface soil of playgrounds in Tokyo, though the contribution of paint chips is smaller than gasoline Pb. 相似文献
523.
Vaughan G Quinn PT Green AC Bean J Roscoe HK van Roozendael M Goutail F 《Journal of environmental monitoring : JEM》2006,8(3):353-361
We present in this paper fifteen years' measurements, from March 1991 to September 2005, of stratospheric NO2 vertical columns measured by a SAOZ zenith-sky visible spectrometer. The instrument spent most of its time at Aberystwyth, Wales, with occasional excursions to other locations. The data have been analysed with the WinDOAS analysis program with low-temperature high-resolution NO2 cross-sections and fitting a slit function to each spectrum. Because of a change in detector in May 1998 there is some uncertainty about the relative changes before and after this date, which are partially constrained by the results of an intercomparison exercise. However, the effect of the Mt Pinatubo aerosol cloud is very evident in the data from 1991-94, with a decrease of 10% in NO2 in the summer of 1992 (the SAOZ was located in Lerwick, Scotland during the winter of 1991-92 and observed very low NO2 values but these cannot be directly compared to the Aberystwyth data). To focus more on interannual and long-term variations in NO2, a seasonal variation comprising an annual and semi-annual component was fitted to the morning and evening twilight separately from 1995 to the present. This fit yielded average NO2 columns of 4.08 x 10(15) cm(-2) and 2.68 x 10(15) cm(-2) for the evening and morning twilight, respectively, with a corresponding annual amplitude of +/-2.08 x 10(15) cm(-2) and +/-1.50 x 10(15) cm(-2). Departures from the fitted curve show a trend of 6% per decade, consistent with that reported elsewhere, for the period 1998-2003, but in the past two years a distinct interannual variation of amplitude of approximately 8% has emerged. 相似文献
524.
Harper M 《Journal of environmental monitoring : JEM》2006,8(6):598-604
Standardized conventions governing the fractions of airborne particles that can penetrate the human head airways, the thoracic airways and the alveolar spaces have been internationally (although not universally) adopted. Several agencies involved in setting limit values for occupational exposure concentrations have taken these conventions into account when considering the appropriate standard for specific chemicals, in order to ensure the standards are biologically relevant. A convention is selected based on the characteristic health effects, and forms the basis of measurement against the limiting concentration value. In order to assess exposure for comparison to this metric or any other purposes, it is necessary to choose a sampler whose performance matches the convention, and protocols have been developed and used to test sampler performance. Several aerosol sampling devices are available, nominally at least, for each of the conventions. Some considerations important to the sampling of airborne particles containing beryllium with regard to the sampling conventions, the test protocols and sampler performance are discussed. 相似文献
525.
Shah MH Shaheen N Khalique A Alrabti AA Jaffar M 《Environmental monitoring and assessment》2006,114(1-3):505-519
Using nitric acid-perchloric acid wet digestion based FAAS method ten selected metals (Cd, Co, Cr, Fe, K, Mn, Na, Ni, Pb and Zn) were determined in the scalp hair of male Pakistani and Libyan donors (n = 62), between 3–54 years age and residing in typical urban areas. The study was taken up to identify sources of metal distribution in two diverse population segments exposed to different environments. Sodium emerged with the highest mean hair concentration of 511.0 μg/g and 496.9 μg/g for Libyan and Pakistani donors respectively, followed by K, at 266.2 μg/g and 242.4 μg/g for the two donor categories. Cadmium showed the lowest mean hair concentration for both Pakistani (0.380 μg/g) and Libyan (0.530 μg/g) donors. Levels of Na, K, Pb, Cr and Cd were higher in hair of Libyan donors compared with Pakistani counterparts which showed higher comparative levels of Zn, Fe, Co, Ni and Mn. Strong metal-to-metal correlations were found between Na–K (r = 0.638) and Cd–Co (r = 0.574) for Pakistani donors, while for Libyan donors, Na–K (r = 0.680) and Fe–Mn (r = 0.624) correlations emerged as strongly significant. Only K was found to have a strong positive correlation (r = 0.611) with age for Pakistani donors while this correlation was significantly negative (r = −0.500) for Libyan donors, probably arising from individual food habits. Other metals showed no viable relationship with age. Principal Component Analysis (PCA) and Cluster Analysis (CA) of the data evidenced food, industrial emissions and automobile emissions as possible sources of metal distribution. The results of the present study are compared with those reported for subjects from other regions of the world. 相似文献
526.
A Characterization of Selected Endocrine Disruptor Compounds in a Portuguese Wastewater Treatment Plant 总被引:1,自引:0,他引:1
Maurício R Diniz M Petrovic M Amaral L Peres I Barceló D Santana F 《Environmental monitoring and assessment》2006,118(1-3):75-87
Anthropogenic compounds that are able to disrupt the endocrine system of wildlife species are a major cause for concern and
have led to a demand for new screening methods. The identification and quantification of endocrine disruptor compounds at
wastewater treatment plant is of major interest to assess the endocrine activity of wastewater treatment plant discharges
into the environment. This study consists of a preliminary survey of concentrations of previously selected endocrine disruptor
compounds, undertaken to establish environmental concentrations and to support a biological program assay exposing freshwater
fish to them. Selected endocrine disrupting chemicals (APEs, bisphenol A and 17 β-estradiol) were measured in samples from a wastewater treatment plant located in Lisbon (Portugal), using recent commercial
enzyme-linked immunosorbent assay kits and also LC-MS/MS. The results show that the wastewater treatment plant treatment process
is efficient on the removal of target endocrine disruptor compounds. However, environmentally significant concentrations are
still present in the treated effluent. The results also show that enzyme-linked immunosorbent assay kit is suitable for routine
analysis of the selected compounds. The results are also useful since the wastewater treatment plant is located in a Mediterranean
region, which results in an effluent with its own characteristics. 相似文献
527.
Zhang Y Ruan L Fasola M Boncompagni E Dong Y Dai N Gandini C Orvini E Ruiz X 《Environmental monitoring and assessment》2006,118(1-3):355-368
The rapidly developing Asian countries may face threatening environmental contamination, that however remains largely unassessed.
We studied persistent trace elements in three wetlands, Poyang Lake, relatively unpolluted, and Tai Lake, and Pearl River
Delta, selected as hotspots of pollution in Central China. We adopted as indicator the Little Egret, a widespread colonial
waterbird, and during 1999 and 2000 we collected and analysed the same samples as for a parallel study we conducted in Pakistan,
e.g. eggs, body feathers of chicks, prey spontaneously regurgitated by the chicks, and sediments at the areas most used by
foraging egrets. The levels of trace-metals at our three study areas were similar, or within the range, of those found in
the few other studies for East Asia, with few exceptions. The concentrations of the various elements were below the threshold
that may affect the survival or reproduction of the birds, and even the highest concentrations relative to background, i.e.
Se in eggs, and Hg in feathers at Pearl Delta, do not pose toxic hazards. In sediments, the levels of trace elements were
lower than the critical levels assumed for contaminated soil, except for alarming high levels of As at Poyang. These results
do not confirm our expectation, that Poyang was relatively uncontaminated, while Tai and Pearl were polluted. Although trace
metal concentration differed significantly among the three study areas, these differences were minor and were not consistent
among elements and samples. The bioaccumulation ratios from sediments through prey, feather and egg, were consistent with
our previous findings for Pakistan. Only Hg exhibited high bioaccumulation, while Se and Zn had low accumulation, and the
other elements no accumulation. This reasserts that feathers of predators such as egrets, may be more sensitive indicators
of environmental contamination for the elements subject to bioaccumulation, whereas the sediments or the organisms low in
the food chain are better indicators for the other elements. 相似文献
528.
Chlorination Byproducts in Drinking Water Produced from Thermal Desalination in United Arab Emirates 总被引:1,自引:0,他引:1
Oil activities in the Arabian Gulf can potentially affect the quality of the intake water available for coastal desalination plants. This paper addresses such situation by investigating the quality of intake water and desalinated water produced by a desalination plant located near a coastal industrial complex in United Arab Emirates (UAE). Analyses of the organic compounds on the intake seawater reported non-detected levels in most samples for the three tested organic groups; namely Polyaromatic Hydrocarbons (PAHs), Phenols, and Polychlorinated Biphenyls (PCBs). Trihalomethanes (THMs) and Haloacetic Acids (HAAs) were also tracked in the intake sea water, throughout the desalination processes, and in the final produced drinking water, to evaluate the undertaken pre- and post chlorination practices. The levels of considered Chlorination Byproducts (CBPs) were mostly found below the permissible international limits with few exceptions showing tangible levels of bromoform in the intake seawater and in the final produced drinking water as well. Lab-controlled experiments on the final produced distillate showed little contribution of its blending with small percentage of seawater upon the formation of trihalomethane and in particular, bromoform. Such results indicate that the organic precursors originated in the seawater are responsible for bromoform formation in the final distillate. 相似文献
529.
Romário J. da Silv Lizeth Carolina Mojica-Sánchez Filipe D.S. Gorz Graciela C. Pedro Bruna G. Maciel Gabriela P. Ratkovski Hérica D. da Roch Kamila T.O. do Nascimento Juan C. Medina-Llamas Alicia E. Chávez-Guajardo José J. Alcaraz-Espinoz Celso P. de Melo 《环境科学学报(英文版)》2021,33(2):62-73
We report the preparation of poly(3,4-ethylene dioxythiophene) (PEDOT)-modified polyvinylidene fluoride electrospun fibers and their use as a novel adsorbent material for the removal of the anionic dye Methyl Orange (MO) from aqueous media. This novel adsorbent material can be used to selectively remove MO on a wide pH range (3.0–10.0), with a maximum capacity of 143.8 mg/g at pH 3.0. When used in a recirculating filtration system, the maximum absorption capacity was reached in a shorter time (20 min) than that observed for batch mode experiments (360 min). Based on the analyses of the kinetics and adsorption isotherm data, one can conclude that the predominant mechanism of interaction between the membrane and the dissolved dye molecules is electrostatic. Besides, considering the estimated values for the Gibbs energy, and entropy and enthalpy changes, it was established that the adsorption process is spontaneous and occurs in an endothermic manner. The good mechanical and environmental stability of these membranes allowed their use in at least 20 consecutive adsorption/desorption cycles, without significant loss of their characteristics. We suggest that the physical-chemical characteristics of PEDOT make these hybrid mats a promising adsorbent material for use in water remediation protocols and effluent treatment systems. 相似文献
530.
Yifei Wang Wending Pan Kee Wah Leong Yingguang Zhang Xiaolong Zhao Shijing Luo Dennis Y.C.Leung 《绿色能源与环境(英文)》2023,(5):1380-1388
Low-cost, flexible and safe battery technology is the key to the widespread usage of wearable electronics, among which the aqueous Al ion battery with water-in-salt electrolyte is a promising candidate. In this work, a flexible aqueous Al ion battery is developed using cellulose paper as substrate. The water-in-salt electrolyte is stored inside the paper, while the electrodes are either printed or attached on the paper surface,leading to a lightweight and thin-film battery prototype. Currently, ... 相似文献