全文获取类型
收费全文 | 343篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 19篇 |
环保管理 | 97篇 |
综合类 | 15篇 |
基础理论 | 100篇 |
污染及防治 | 69篇 |
评价与监测 | 29篇 |
社会与环境 | 15篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 3篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 11篇 |
2013年 | 24篇 |
2012年 | 10篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 17篇 |
2008年 | 20篇 |
2007年 | 28篇 |
2006年 | 11篇 |
2005年 | 14篇 |
2004年 | 13篇 |
2003年 | 11篇 |
2002年 | 10篇 |
2001年 | 10篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有354条查询结果,搜索用时 0 毫秒
241.
242.
The negative effects of unemployment on psychological health are well documented, yet Kasl's ( 1982 ) reverse causation hypothesis is that positive psychological health, and in particular self‐esteem, facilitates re‐employment. The aim of this study was to investigate this proposal by assessing levels of self‐esteem, cognitive appraisals and coping efforts among unemployed persons and relating these factors to their employment status six months later. Two hundred and one unemployed (49 per cent female, 51 per cent male; mean age = 32.41 ± 10.18 years) and 128 employed respondents (59 per cent female, 41 per cent male; mean age = 35.0 ± 11.73 years) participated in the study. Participants completed the Adult Self‐Perception Profile, Access to Categories of Experience, Locus of Control, Deakin Coping Scale, and the Meaningful Leisure Activities Questionnaire at baseline and at six‐month follow‐up using a mail‐out survey. Comparison of baseline appraisals revealed that future re‐employed participants rated their latent deprivation lower and their internal locus of control higher than those continuously unemployed, and they also derived more internal meaning from leisure activities. Overall, the results provide support for Kasl's reverse causation hypothesis extended to these other domains of psychological health. Intervention strategies designed to incorporate the promotion of these factors are discussed. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
243.
244.
Ian D. Moore 《Journal of the American Water Resources Association》1983,19(6):961-965
ABSTRACT: Precipitation, throughfall, and stream pH were measured weekly over a 27-week period in 1982 on the Little Millseat watershed in eastern Kentucky. The average pH values over the study period were 4.3, 4.9, and 6.4, respectively, indicating significant buffering as water moved from the atmosphere, through the deciduous canopy, and through or over the soil to the stream. Regression analysis demonstrated that the timing and amount of precipitation were important factors influencing the pH of the throughfall. Weekly precipitation and the three-week average precipitation were statistically significant variables, explaining 53 percent of the variance in the observed through- fall pH. Precipitation pH was not a statistically significant variable for this watershed and sampling period. 相似文献
245.
G. R. Sands I. D. Moore C. R. Roberts 《Journal of the American Water Resources Association》1982,18(5):831-839
ABSTRACT: A computer model was developed in order to establish a yield predictive relationship and to estimate the water requirements for supplemental irrigation of horticultural crops in the humid region. Alternative distribution systems were developed and designed using the results from the computer model and Wood's (1980) pipe network algorithm. The capital, operational, and maintenance costs of the distribution and recommended on-farm irrigation systems were determined and used to evaluate the economic feasibility of the alternative designs. Results show that the concentration of irrigated area along the distribution system, the length of the distribution system, and cropping system all have an important effect on the economic feasibility of supplemental irrigation in Wayne County, Kentucky. 相似文献
246.
T. R. Moore 《Journal of the American Water Resources Association》1987,23(5):785-791
ABSTRACT: Runoff and ground-water samples were collected from four ombrotrophic bogs, representing undisturbed and drained/harvested conditions, at two-week intervals during the summer of 1984. Analyses of samples for water quality parameters revealed significant (P < 0.05 level) increases in specific conductance, NH4+-N, total dissolved P, Mg, K, and Na and a decrease in the E4:E6 ratio (suggesting increased proportions of humic acid) associated with drainage. There were no significant changes in dissolved organic carbon, Ca concentrations, or pH. Comparison of samples collected before, during, and after ditching showed increases in the dissolved organic carbon, NH4+-N, total dissolved P, K, and Na and a decrease in the E4:E6 ratio, but these changes were short lived; water quality returned to preditching values after about a week. The observed changes in water quality are small, probably because the peat is very acid (pH 3.0 to 4.5). 相似文献
247.
Gerald K. Moore Gary W. North 《Journal of the American Water Resources Association》1974,10(5):1082-1096
ABSTRACT: Panchromatic black and white, color, and color infrared photographs and thermal infrared imagery are compared for a capability to show flood boundaries. In open agricultural and urban areas, these boundaries are easily delineated on all types of am. Boundaries are more difficult to see in wooded areas. In March, hardwood trees are dormant, but black and white photographs and color photographs show only the tops of these trees. Color infrared photographs in January and March have a distinctive color or tone in inundated woods; the limit of this tone is the flood boundary. Daytime thermal infrared imagery in March shows that inundated woods are cooler than dry land but warmer than open water. After about April 1, both color infrared photography and thermal infrared imagery show only the top of the tree canopy and do not reflect underlying flood water. Inundated areas can be delineated easily on ERTS satellite imagery from December through March. On imagery from May 4–5, 1973, however, most inundation boundaries had to be drawn as dashed lines; the tree canopy obscures flood waters in wooded areas. Despite this problem, the results of mapping flood boundaries on May imagery are believed to be reasonable for the scale of the imagery. 相似文献
248.
Barry C. Moore Ping-Hung Chen William H. Funk David Yonge 《Journal of the American Water Resources Association》1996,32(4):723-731
ABSTRACT: Hypolimnetic aeration is a widely used technique for lake restoration and fisheries enhancement. However, system design still depends on application of “safety factors” to observed oxygen demand rates, in large part because actual oxygen demand may be greater after aeration than before. Laboratory incubations of sediment show that sediment oxygen demand (SOD) rates follow mixed order kinetics, with an initial period of zero order reaction, followed by first order kinetics. The transition from zero to first order kinetics may correspond to the transition from laminar to turbulent flow. This suggests that SOD reaction kinetics are governed by thickness of the diffusive sublayer adjacent to the sediments. Therefore, zero and first order reaction regions correspond with oxygen diffusion limitation and substrate limitation, respectively. Such a mechanism would account for the induced oxygen demand observed following hypolimnetic aeration and would reconcile differences in SOD reaction orders noted in the literature. This paper describes development of equations based on laboratory SOD incubations for predicting induced oxygen demand following hypolimnetic aeration. 相似文献
249.
Understanding the processes that determine the solid-liquid partitioning (K(d) value) of Se is of fundamental importance in assessing the risk associated with the disposal of radio-selenium-containing waste. Using a mini-column (rather than batch) approach, K(d) values for (75)Se were determined over time in relation to soil moisture content (field capacity or saturated), redox potential and methyl bromide fumigation (used to disrupt the soil microbial population) in three contrasting soil types: clay loam, organic and sandy loam. The K(d) values were generally in the range 50-500 L kg(-1), with mean soil K(d) increasing with increasing organic matter content. Saturation with water lowered the measured redox potentials in the soils. However, only in the sandy loam soil did redox potential become negative, and this led to an increase in (75)Se K(d) value in this soil. Comparison of the data with the Eh-pH stability diagram for Se suggested that such strong reduction may have been consistent with the formation of the insoluble Se species, selenide. These findings, coupled with the fact that methyl bromide fumigation had no discernible effect on (75)Se K(d) value in the sandy loam soil, suggest that geochemical, rather than microbial, processes controlled (75)Se partitioning. The inter-relations between soil moisture content, redox potential and Se speciation should be considered in the modelling and assessment of radioactive Se fate and transport in the environment. 相似文献
250.
Female Penaeus esculentus Haswell were collected by 15 to 20 min duration trawls during 1990. Carotenoids were analysed in the digestive gland, abdominal muscle, the remainder of the body (hereafter called integument) and ovary of prawns in Stage 2 through Stage 4 (fully mature) of maturation. The only oxycarotenoids (xanthophylls) identified were astaxanthins or astaxanthin esters; occasionally low levels of -carotene were detected in the digestive gland. The concentrations of astaxanthin monoesters (AM) and diesters (AD) were highest, with only minor amounts of free astaxanthins (Ast), except in the maturing ovaries, where free astaxanthins predominated (up to 80% of the total carotenoid). Of the total carotenoid, 82 to 94% was in the integument, but at maturity the digestive gland contained 10.7±3.4% and the ovary 5.6±0.9% of the total carotenoid. Only the ovary increased in mass during maturation, reaching up to 5.2% of total prawn mass. During this period, digestive gland concentrations of AM, AD and Ast all increased (tota 20 to 120 g g-1); levels in the muscle and integument varied little throughout maturation (total 0.4 and 100 g g-1, respectively); ovary AM levels remained low throughout (1.5 to 1.2 g g-1), AD increased from only 2 to 5 g g-1, but Ast increased from 2 to 34 g g-1. Apart from the ovary, AM concentrations were the most variable. In common with other decapod Crustacea, the maturing ovary of P. esculentus contained high levels of carotenoids, indicating that these may have an important role in early development. The natural diet of P. esculentus includes a variety of carotenoids, but except for a little -carotene, the digestive gland, where absorption occurs, contained astaxanthins, with only an occasional trace of -carotene. This suggests that the conversion of dietary carotenoids to astaxanthin occurs soon after ingestion. 相似文献