全文获取类型
收费全文 | 280篇 |
免费 | 3篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 12篇 |
废物处理 | 3篇 |
环保管理 | 44篇 |
综合类 | 126篇 |
基础理论 | 30篇 |
污染及防治 | 61篇 |
评价与监测 | 4篇 |
社会与环境 | 13篇 |
灾害及防治 | 1篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2013年 | 29篇 |
2012年 | 4篇 |
2011年 | 17篇 |
2010年 | 6篇 |
2008年 | 4篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 6篇 |
2004年 | 10篇 |
2003年 | 6篇 |
2002年 | 11篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1992年 | 3篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1980年 | 7篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 4篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1969年 | 7篇 |
1967年 | 4篇 |
1966年 | 4篇 |
1965年 | 4篇 |
1964年 | 2篇 |
1963年 | 4篇 |
1962年 | 9篇 |
1961年 | 3篇 |
1960年 | 5篇 |
1959年 | 6篇 |
1958年 | 4篇 |
1957年 | 8篇 |
1956年 | 4篇 |
1955年 | 3篇 |
1933年 | 2篇 |
1932年 | 3篇 |
1923年 | 2篇 |
排序方式: 共有294条查询结果,搜索用时 430 毫秒
221.
Robert B. McKusick Richard M. Adams J. Herbert Snyder 《Journal of the American Water Resources Association》1977,13(3):489-498
ABSTRACT: This paper evolved from a concern that water resource administrators and planners do not have a consistent definition of the value of goods and services of outputs from projects and programs. A more flexible approach to planning and evaluation is presented that recognizes the interaction of production and consumption through the use of commodity demand curves. Use of the concept of consumer surplus permits measurement of the differential impacts on producers' and consumers' welfare. Quadratic programming is suggested as a consistent means of quantifying these differential impacts. 相似文献
222.
Peter N. Nemetz Herbert D. Drechsler 《Journal of the American Water Resources Association》1980,16(6):1084-1093
ABSTRACT: The hypothesis of this paper is that regulatory systems for the control of effluent released to the environment can be, if improperly designed, inadequate for both the establishment of effective pollution control policy and the assessment of the biological significance of violations. This inadequacy may stem from several factors: first, the use of single point standards which delineate the boundary between legally acceptable and unacceptable pollutant discharges; and second, the existence of significant weaknesses in the frequency and design of monitoring programs. In order to be effective, pollution standards must reflect the impact of pollutants on the ecosystem. To achieve this goal, three critical pieces of information are required: measurement of ambient levels of released pollutants, frequency distributions derived from these data, and estimates of biological damage functions. Illustrating the above three requirements with data drawn from research in British Columbia, the authors recommended a restructuring of environmental policy to provide regulatory agencies with an effective mechanism for the analysis and control of environmental degradation. 相似文献
223.
224.
Comparisons of forager distributions from matched honey bee colonies in suburban environments 总被引:4,自引:0,他引:4
Keith D. Waddington Thomas J. Herbert P. Kirk Visscher Monica Raveret Richter 《Behavioral ecology and sociobiology》1994,35(6):423-429
We conducted experiments designed to examine the distribution of foraging honey bees (Apis mellifera) in suburban environments with rich floras and to compare spatial patterns of foraging sites used by colonies located in the same environment. The patterns we observed in resource visitation suggest a reduced role of the recruitment system as part of the overall colony foraging strategy in habitats with abundant, small patches of flowers. We simultaneously sampled recruitment dances of bees inside observation hives in two colonies over 4 days in Miami, Florida (1989) and from two other colonies over five days in Riverside, California (1991). Information encoded in the dance was used to determine the distance and direction that bees flew from the hive for pollen and nectar and to construct foraging maps for each colony. The foraging maps showed that bees from the two colonies in each location usually foraged at different sites, but occasionally they visited the same patches of flowers. Each colony shifted foraging effort among sites on different days. In both locations, the mean flight distances differed between colonies and among days within colonies. The flight distances observed in our study are generally shorter than those reported in a similar study conducted in a temperate deciduous forest where resources were less dense and floral patches were smaller. 相似文献
225.
Edward P. Hardy Herbert L. Volchok Hugh D. Livingston John C. Burke 《Environment international》1980,4(1):21-30
A sediment core from a lake downwind of the Rocky Flats Plant, where nuclear weapons components are produced, was used to reconstruct a time pattern of off-site plutonium deposition. Core sections were dated by analyses of 137Cs, 239,240Pu, 238Pu, and 241Am fallout from nuclear testing and 238Pu fallout from a satellite failure. A peak in transuranic concentrations occurred in late 1969 which was attributable to the Plant. This was confirmed by mass isotopic analysis of plutonium isotopes in selected core segments where the global fallout and Plant contributions could be differentiated. The 18 nCi 239,240Pu per m2 from the Plant that had accumulated in the sediment is reasonable when compared to soil analyses. 相似文献
226.
Herbert Fennerty 《The Environmentalist》2006,26(2):93-98
There are many examples in the developing countries (DCs) of environmental standards being set at high levels that cannot
possibly be met in the prevailing economic conditions. Such standards are counter-productive; responsible operators who would
work towards reasonable standards are turned off and evade the standards. This situation arises because the selected standards
tend to be copies of existing standards from industrialized countries where most of the work of developing standards has taken
place. The standards they copy are the current high standards that are affordable in the West, but are not affordable in the
DCs.
A similar situation exists with respect to technology. Designs that work well in the West tend to be copied but do not function
well in the DCs because the level of expertise needed to ensure proper performance does not exist, and cannot be recruited
and retained at the low wage levels that most authorities are able to pay.
The remedy in both cases is to ensure that standards are appropriate and that the constructed facilities will be appropriate
and sustainable. They can be sustainable only if adequate funds are assured for a sound program of operation and maintenance.
With the ever increasing competition for the use of scarce water resources, all control agencies have a duty to maximize the
use of the water they are allocated. For urban water supply systems this means ensuring tight control of UFW. Privatization
of UFW control may offer significant benefits for the DCs and merits serious consideration. 相似文献
227.
Herbert C. Preul Constantine N. Papadakis 《Journal of the American Water Resources Association》1973,9(2):291-300
ABSTRACT A synthetic storm rainfall hyetograph for a one-year design frequency is derived from the one-year intensity-duration curve developed for Cincinnati, Ohio. Detailed rainfall data for a three-year period were collected from three raingages triangulating the Bloody Run Sewer Watershed, an urban drainage areas of 2380 acres'in Cincinnati, Ohio. The advancement of the synthetic storm pattern is obtained from an analysis of the antecedent precipitation immediately preceding the maximum period of three selected durations. Rains which produced excessive runoff at least for some duration were considered only. The same approach can be used for other design frequencies. The purpose of this study is to provide synthetic storm hyetographs to be used as input in deterministic mathematical models simulating urban storm water runoff for the design, analysis and possible surcharge prediction of sewer systems. 相似文献
228.
Research on perception of parks and recreation settings has examined several important tree attributes that influence people's
visual preferences. This research, however, has usually not considered the spatial arrangement of the trees, partly because
of the lack of adequate methods for representing tree arrangements with systematically manipulated geometries. In the study
reported here, computer video-imaging techniques were used to construct simulated landscape scenes that varied on specific
dimensions of the spatial configuration of trees. The simulations were rated for visual preference by three respondent groups:
a university class, a bicycle club, and a women's civic group. Preference ratings were significantly influenced by the number
of trees in the scene, by the number of clumps into which trees were grouped, and by the diameter of the clumps. The video-imaging
technology implemented in this study offers important methodological advantages for the design of carefully controlled experiments
to study human response to variation in landscape treatments. 相似文献
229.
Optimal foraging strategies and food choice are influenced by various factors, e.g. availability, size and caloric content of the food type and predation risk. However, food choice criteria may change when food is not eaten immediately but has to be carried to a storage site for later use. For example, handling time in terms of harvesting and transport time should be optimized, particularly when the risk of predation is high. Thus, it is not clear whether food selected by hoarding animals reflects their food preference due to intrinsic features of the food type, e.g. size, caloric or lipid content, or whether the food type selected is a compromise that also considers the handling time required for harvesting and transport. We investigate this question in relation to food hoarding behaviour in mound-building mice. In autumn, mound-building mice Mus spicilegus collect seeds and other plant material and cover it with soil. Such above-ground storage is quite unusual for rodents. Here, we investigated whether there is a relationship between the seed species preferred as building materials and those preferred for food. We conducted a seed preference test using three most collected weed species for mound building. Controlling factors like food availability or predation risk, mice prefer Setaria spp. as food, although Amaranthus spp. and Chenopodium spp. were preferentially harvested and stored. By including the availability of the three species, our experimental results were confirmed, namely, a clear preference for Setaria spp. Also, handling time and seed size revealed to influence plant choice. 相似文献
230.
The accumulation of natural and artificial radionuclides in humans and domestic animals is of interest in estimating effective doses of exposed humans and to decide whether animal products can be used for nutrition of the population. In this paper we present an investigation of the (137)Cs- and (40)K-activity levels of the ribs and sternum of a "mountain pasture" cow, born in a highly contaminated region of Styria, Austria, at the time of the radioactive fallout following the Chernobyl accident. This is the first systematic investigation of the variation in activity levels of a contaminated animal. The International Commission on Radiological Protection (ICRP) assumes that cesium and potassium are homogenously distributed throughout the whole body of an organism. However, the presented results show that there is a non-uniform distribution of (137)Cs and (40)K in different skeletal bones and their adherent tissues of a dairy cattle. We found that activity concentrations of (137)Cs and (40)K varied up to a factor 2.5 in different components of the ribs. The minimum values of (137)Cs and (40)K in the ribs were 29.9 and 21Bqkg(-1) fresh mass for trabecular bone in the vertebral half of asternal ribs, and the maximum values 332 and 132Bqkg(-1) fresh mass for a mixed sample composed of a cartilaginous tissue layer and parts of the perichondrium, both originating from asternal costal cartilages, respectively. 相似文献